Hosts page: grouped file filter with counts and source-path projection

Add SourcePathFilter to HostsPageQueryState and apply it in HostsPageProjectionService.
Replace the native select with a grouped menu (managed/system/additional/hostsdir),
per-file non-comment counts, toolbar layout, and full-path labels with end-anchored
ellipsis plus title tooltips. Include HostsSourcePathDisplay helpers, menu models,
and tests for grouping and projection filtering.

src/DnsmasqWebUI.Tests/Models/Hosts/HostsSourcePathDisplayTests.cs

@@ -0,0 +1,55 @@
+using DnsmasqWebUI.Models.Hosts;
+
+namespace DnsmasqWebUI.Tests.Models.Hosts;
+
+public sealed class HostsSourcePathDisplayTests
+{
+    private static HostsPageRow Row(HostsRowSourceKind kind, string path, bool isComment = false) =>
+        new(
+            Id: "id",
+            SourceKind: kind,
+            SourcePath: path,
+            IsEditable: false,
+            IsActive: true,
+            InactiveReason: null,
+            Address: "127.0.0.1",
+            Names: [],
+            EffectiveNames: [],
+            IsComment: isComment,
+            LineNumber: 1);
+
+    [Fact]
+    public void BuildFileFilterMenuGroups_InjectsManagedPath_WhenNotInRows()
+    {
+        var managed = "/data/managed.hosts";
+        var groups = HostsSourcePathDisplay.BuildFileFilterMenuGroups([], managed);
+
+        Assert.Single(groups);
+        Assert.Equal(HostsRowSourceKind.Managed, groups[0].SourceKind);
+        Assert.Single(groups[0].Files);
+        Assert.Equal(managed, groups[0].Files[0].Path);
+        Assert.Equal(0, groups[0].Files[0].RecordCount);
+    }
+
+    [Fact]
+    public void BuildFileFilterMenuGroups_OrdersGroupsManagedSystemAddn_AndCountsNonComments()
+    {
+        var rows = new[]
+        {
+            Row(HostsRowSourceKind.SystemHosts, "/etc/hosts"),
+            Row(HostsRowSourceKind.Managed, "/m/a.hosts"),
+            Row(HostsRowSourceKind.Managed, "/m/a.hosts", isComment: true),
+            Row(HostsRowSourceKind.AddnHosts, "/extra/b.hosts"),
+        };
+
+        var groups = HostsSourcePathDisplay.BuildFileFilterMenuGroups(rows, managedHostsPathAlwaysShow: null);
+
+        Assert.Equal(3, groups.Count);
+        Assert.Equal(HostsRowSourceKind.Managed, groups[0].SourceKind);
+        Assert.Equal(HostsRowSourceKind.SystemHosts, groups[1].SourceKind);
+        Assert.Equal(HostsRowSourceKind.AddnHosts, groups[2].SourceKind);
+
+        Assert.Single(groups[0].Files);
+        Assert.Equal(1, groups[0].Files[0].RecordCount);
+    }
+}

src/DnsmasqWebUI.Tests/Services/Hosts/HostsPageProjectionServiceTests.cs

@@ -0,0 +1,80 @@
+using DnsmasqWebUI.Infrastructure.Services.Dnsmasq.Hosts;
+using DnsmasqWebUI.Models.Hosts;
+
+namespace DnsmasqWebUI.Tests.Services.Hosts;
+
+public class HostsPageProjectionServiceTests
+{
+    private readonly HostsPageProjectionService _sut = new();
+
+    [Fact]
+    public void BuildGroups_SourcePathFilter_KeepsOnlyThatFile()
+    {
+        var rows = new HostsPageRow[]
+        {
+            new(
+                "m1",
+                HostsRowSourceKind.Managed,
+                "/data/managed.hosts",
+                IsEditable: true,
+                IsActive: true,
+                InactiveReason: null,
+                Address: "10.0.0.1",
+                Names: new[] { "a" },
+                EffectiveNames: new[] { "a" },
+                IsComment: false,
+                LineNumber: 1),
+            new(
+                "x1",
+                HostsRowSourceKind.AddnHosts,
+                "/etc/extra.hosts",
+                IsEditable: false,
+                IsActive: true,
+                InactiveReason: null,
+                Address: "10.0.0.2",
+                Names: new[] { "b" },
+                EffectiveNames: new[] { "b" },
+                IsComment: false,
+                LineNumber: 1),
+        };
+
+        var query = new HostsPageQueryState(
+            Search: "",
+            Grouping: HostsGroupingMode.Source,
+            Sort: HostsSortMode.LineNumber,
+            Descending: false,
+            SourceKindFilter: null,
+            SourcePathFilter: "/etc/extra.hosts",
+            EditableFilter: null,
+            ActiveFilter: null);
+
+        var groups = _sut.BuildGroups(rows, query);
+
+        Assert.Single(groups);
+        Assert.Equal("/etc/extra.hosts", groups[0].Subtitle);
+        Assert.Single(groups[0].Rows);
+    }
+
+    [Fact]
+    public void BuildGroups_SourcePathFilter_EmptyMeansAllFiles()
+    {
+        var rows = new HostsPageRow[]
+        {
+            new("m1", HostsRowSourceKind.Managed, "/a", true, true, null, "1.1.1.1", new[] { "a" }, new[] { "a" }, false, 1),
+            new("x1", HostsRowSourceKind.AddnHosts, "/b", false, true, null, "2.2.2.2", new[] { "b" }, new[] { "b" }, false, 1),
+        };
+
+        var query = new HostsPageQueryState(
+            "",
+            HostsGroupingMode.Source,
+            HostsSortMode.LineNumber,
+            false,
+            null,
+            SourcePathFilter: null,
+            null,
+            null);
+
+        var groups = _sut.BuildGroups(rows, query);
+        Assert.Equal(2, groups.Count);
+    }
+}

src/DnsmasqWebUI/Components/Pages/Hosts.razor

@@ -69,19 +69,79 @@ else
         <section class="page-section">
             <h2 class="page-section-title mb-3">Hosts entries</h2>
 
-            <div class="hosts-controls-bar d-flex justify-content-between align-items-center mb-3 flex-wrap gap-2">
+            <div class="hosts-controls-bar d-flex justify-content-between align-items-center mb-3 flex-wrap gap-2"
-                <div class="d-flex flex-wrap gap-2 align-items-center flex-grow-1">
+                 @onkeydown="OnHostsToolbarKeyDown">
+                <div class="hosts-toolbar-fields flex-grow-1">
                     <input type="text"
                            class="form-control form-control-sm hosts-toolbar-search"
                            placeholder="Search address, names, path…"
                            @bind="_search"
                            @bind:event="oninput" />
+                    <label class="visually-hidden" for="hosts-file-filter-trigger">Hosts file</label>
+                    <div class="hosts-file-filter-wrap @(_fileFilterMenuOpen ? "hosts-file-filter-wrap--open" : null)">
+                        @if (_fileFilterMenuOpen)
+                        {
+                            <div class="hosts-file-filter-backdrop" @onclick="CloseFileFilterMenu" aria-hidden="true"></div>
+                        }
+                        <button type="button"
+                                id="hosts-file-filter-trigger"
+                                class="hosts-file-filter-toggle hosts-toolbar-file-filter"
+                                title="Show entries from all loaded hosts files, or only one file"
+                                aria-label="Filter by hosts file"
+                                aria-haspopup="listbox"
+                                aria-expanded="@(_fileFilterMenuOpen ? "true" : "false")"
+                                aria-controls="hosts-file-filter-menu"
+                                @onclick="ToggleFileFilterMenu"
+                                @onclick:stopPropagation="true">
+                            <span class="hosts-file-filter-toggle-label text-truncate">@FileFilterSummaryText</span>
+                            <i class="bi bi-chevron-down hosts-file-filter-chevron flex-shrink-0" aria-hidden="true"></i>
+                        </button>
+                        @if (_fileFilterMenuOpen)
+                        {
+                            <div id="hosts-file-filter-menu"
+                                 class="hosts-file-filter-panel shadow"
+                                 role="listbox"
+                                 aria-label="Hosts files"
+                                 @onclick:stopPropagation="true">
+                                <button type="button"
+                                        class="hosts-file-filter-option hosts-file-filter-option--all @(string.IsNullOrWhiteSpace(_sourceFileFilter) ? "hosts-file-filter-option--active" : null)"
+                                        role="option"
+                                        aria-selected="@(string.IsNullOrWhiteSpace(_sourceFileFilter) ? "true" : "false")"
+                                        @onclick="@(() => SelectSourceFileFilter(""))">
+                                    <span class="hosts-file-filter-option-main">All files</span>
+                                    <span class="hosts-file-filter-count">@HostsTotalDataRowCount</span>
+                                </button>
+                                @foreach (var group in FileFilterMenuGroups)
+                                {
+                                    <div class="hosts-file-filter-group hosts-file-filter-group--@FileFilterGroupKindClass(group.SourceKind)">
+                                        <div class="hosts-file-filter-group-header" role="presentation">
+                                            <span class="hosts-file-filter-group-title">@group.Title</span>
+                                        </div>
+                                        @foreach (var file in group.Files)
+                                        {
+                                            var path = file.Path;
+                                            var active = IsSourceFilePathSelected(path);
+                                            <button type="button"
+                                                    class="hosts-file-filter-option @(active ? "hosts-file-filter-option--active" : null)"
+                                                    role="option"
+                                                    aria-selected="@(active ? "true" : "false")"
+                                                    title="@path"
+                                                    @onclick="@(() => SelectSourceFileFilter(path))">
+                                                <span class="hosts-file-filter-option-main hosts-file-filter-path" title="@path">@path</span>
+                                                <span class="hosts-file-filter-count">@file.RecordCount</span>
+                                            </button>
+                                        }
+                                    </div>
+                                }
+                            </div>
+                        }
+                    </div>
                 </div>
             </div>
 
             @if (VisibleGroups.Count == 0)
             {
-                <p class="text-muted">No hosts entries found.</p>
+                <p class="text-muted">@(string.IsNullOrWhiteSpace(_sourceFileFilter) ? "No hosts entries found." : "No hosts entries for the selected file.")</p>
             }
             else
             {
@@ -89,6 +149,10 @@ else
                 {
                     <p class="text-muted">No rows match the current search.</p>
                 }
+                else if (TotalVisibleDataRows == 0 && !string.IsNullOrWhiteSpace(_sourceFileFilter))
+                {
+                    <p class="text-muted">No rows match the current filters.</p>
+                }
                 <div class="app-table-scroll-shell" data-table-scroll-cue>
                     <div class="app-table-scroll-region" data-table-scroll-region role="region" aria-label="Hosts entries table" tabindex="0"
                          @onkeydown="OnHostsTableRegionKeyDown">
@@ -128,7 +192,7 @@ else
                                                         <span class="badge bg-warning text-dark">Inactive</span>
                                                     }
                                                 </div>
-                                                <div class="hosts-group-header__path-row">
+                                                <div class="hosts-group-header__path-row @(IsManagedEditableGroup(group) ? "hosts-group-header__path-row--with-managed-actions" : null)">
                                                     <div class="hosts-group-header__path">
                                                         @if (!string.IsNullOrWhiteSpace(group.Subtitle))
                                                         {
@@ -406,6 +470,8 @@ else
     private string? _error;
 
     private string _search = "";
+    /// <summary>Empty = all hosts files; otherwise matches <see cref="HostsPageRow.SourcePath"/>.</summary>
+    private string _sourceFileFilter = "";
 
     private readonly HashSet<string> _selectedManagedRowIds = new(StringComparer.Ordinal);
 
@@ -431,6 +497,7 @@ else
     private object? _visibleGroupsCacheRowsRef;
     private string _visibleGroupsCacheSearch = "\0";
     private string _visibleGroupsCacheManagedPath = "\0";
+    private string _visibleGroupsCacheSourcePathFilter = "\0";
 
     private IReadOnlyList<HostsPageGroup> VisibleGroups
     {
@@ -440,7 +507,8 @@ else
             if (_visibleGroupsCache != null
                 && ReferenceEquals(_visibleGroupsCacheRowsRef, _unifiedRows)
                 && _visibleGroupsCacheSearch == _search
-                && _visibleGroupsCacheManagedPath == managedPath)
+                && _visibleGroupsCacheManagedPath == managedPath
+                && _visibleGroupsCacheSourcePathFilter == _sourceFileFilter)
             {
                 return _visibleGroupsCache;
             }
@@ -450,6 +518,7 @@ else
             _visibleGroupsCacheRowsRef = _unifiedRows;
             _visibleGroupsCacheSearch = _search;
             _visibleGroupsCacheManagedPath = managedPath;
+            _visibleGroupsCacheSourcePathFilter = _sourceFileFilter;
             return _visibleGroupsCache;
         }
     }
@@ -512,6 +581,10 @@ else
         if (groups.Any(g => g.SourceKind == HostsRowSourceKind.Managed))
             return groups;
 
+        if (!string.IsNullOrWhiteSpace(_sourceFileFilter)
+            && !string.Equals(_sourceFileFilter.Trim(), path, StringComparison.OrdinalIgnoreCase))
+            return groups;
+
         var placeholder = new HostsPageGroup(
             Key: $"{HostsRowSourceKind.Managed}:{path}",
             Title: "Managed hosts",
@@ -535,10 +608,99 @@ else
             Sort: HostsSortMode.LineNumber,
             Descending: false,
             SourceKindFilter: null,
+            SourcePathFilter: string.IsNullOrWhiteSpace(_sourceFileFilter) ? null : _sourceFileFilter.Trim(),
             EditableFilter: null,
             ActiveFilter: null);
     }
 
+    private bool _fileFilterMenuOpen;
+
+    private IReadOnlyList<HostsFileFilterMenuGroup> FileFilterMenuGroups =>
+        HostsSourcePathDisplay.BuildFileFilterMenuGroups(_unifiedRows, _status?.ManagedHostsFilePath);
+
+    private int HostsTotalDataRowCount => _unifiedRows.Count(r => !r.IsComment);
+
+    private string FileFilterSummaryText
+    {
+        get
+        {
+            if (string.IsNullOrWhiteSpace(_sourceFileFilter))
+            {
+                var n = HostsTotalDataRowCount;
+                return n == 0 ? "All files" : $"All files · {n} records";
+            }
+
+            var trimmed = _sourceFileFilter.Trim();
+            foreach (var g in FileFilterMenuGroups)
+            {
+                foreach (var f in g.Files)
+                {
+                    if (string.Equals(f.Path, trimmed, StringComparison.OrdinalIgnoreCase))
+                    {
+                        var prefix = HostsSourcePathDisplay.GroupSummaryPrefix(g.SourceKind);
+                        return $"{prefix} · {f.FileName} ({f.RecordCount})";
+                    }
+                }
+            }
+
+            return HostsSourcePathDisplay.FormatOptionLabel(trimmed);
+        }
+    }
+
+    private void ToggleFileFilterMenu() => _fileFilterMenuOpen = !_fileFilterMenuOpen;
+
+    private void CloseFileFilterMenu() => _fileFilterMenuOpen = false;
+
+    private void SelectSourceFileFilter(string path)
+    {
+        _sourceFileFilter = path ?? "";
+        CloseFileFilterMenu();
+        OnSourceFileFilterChangedAfterBind();
+    }
+
+    private async Task OnHostsToolbarKeyDown(KeyboardEventArgs e)
+    {
+        if (!_fileFilterMenuOpen || e.Key != "Escape")
+            return;
+        CloseFileFilterMenu();
+        await InvokeAsync(StateHasChanged);
+    }
+
+    private bool IsSourceFilePathSelected(string path) =>
+        !string.IsNullOrWhiteSpace(_sourceFileFilter)
+        && string.Equals(_sourceFileFilter.Trim(), path.Trim(), StringComparison.OrdinalIgnoreCase);
+
+    private static string FileFilterGroupKindClass(HostsRowSourceKind kind) => kind switch
+    {
+        HostsRowSourceKind.Managed => "managed",
+        HostsRowSourceKind.SystemHosts => "system",
+        HostsRowSourceKind.AddnHosts => "addn",
+        HostsRowSourceKind.Hostsdir => "hostsdir",
+        _ => "other"
+    };
+
+    private void OnSourceFileFilterChangedAfterBind()
+    {
+        InvalidateVisibleGroupsCache();
+        StateHasChanged();
+    }
+
+    private void NormalizeSourceFileFilterIfStale()
+    {
+        if (string.IsNullOrWhiteSpace(_sourceFileFilter))
+            return;
+        var f = _sourceFileFilter.Trim();
+        var inRows = _unifiedRows.Any(r => string.Equals(r.SourcePath, f, StringComparison.OrdinalIgnoreCase));
+        var managed = _status?.ManagedHostsFilePath?.Trim();
+        var isManagedPath = !string.IsNullOrEmpty(managed)
+            && string.Equals(managed, f, StringComparison.OrdinalIgnoreCase);
+        if (!inRows && !isManagedPath)
+        {
+            _sourceFileFilter = "";
+            InvalidateVisibleGroupsCache();
+        }
+    }
+
     private void InvalidateVisibleGroupsCache()
     {
         _visibleGroupsCache = null;
@@ -777,6 +939,13 @@ else
         if (_showRemoveHostsModal || _showInvalidHostEditModal)
             return;
 
+        if (_fileFilterMenuOpen && e.Key == "Escape")
+        {
+            CloseFileFilterMenu();
+            await InvokeAsync(StateHasChanged);
+            return;
+        }
+
         if (IsInlineEditing)
         {
             // Scroll region is focusable (tabindex=0); after clicking outside inputs, Escape must still exit edit.
@@ -1193,6 +1362,7 @@ else
                 _unifiedRows = Array.Empty<HostsPageRow>();
             }
 
+            NormalizeSourceFileFilterIfStale();
             InvalidateVisibleGroupsCache();
             _selectedManagedRowIds.Clear();
             _selectionAnchorRowId = null;
@@ -1235,6 +1405,7 @@ else
         }
 
         _unifiedRows = managedRows.Concat(_restUnifiedRows).ToList();
+        NormalizeSourceFileFilterIfStale();
         ClearStaleInlineEditState();
         PruneManagedSelectionToExistingEditableRows();
     }

src/DnsmasqWebUI/Components/Pages/Hosts.razor.css

@@ -58,9 +58,214 @@
     box-shadow: 0 10px 24px -18px rgba(15, 23, 42, 0.35);
 }
 
+/* Search + file filter on one row; search grows, select keeps a stable width. */
+.hosts-toolbar-fields {
+    display: flex;
+    flex-wrap: nowrap;
+    align-items: stretch;
+    gap: 0.5rem;
+    min-width: 0;
+}
+
 .hosts-toolbar-search {
-    min-width: 14rem;
+    flex: 1 1 12rem;
-    max-width: 24rem;
+    min-width: 0;
+    width: auto;
+    max-width: none;
+}
+
+/* File filter: wrapper keeps toolbar flex slot; menu layers above table when open. */
+.hosts-file-filter-wrap {
+    position: relative;
+    flex: 0 0 auto;
+    min-width: 13.5rem;
+    max-width: 22rem;
+    width: auto;
+}
+
+.hosts-file-filter-wrap--open {
+    z-index: 1080;
+}
+
+.hosts-file-filter-backdrop {
+    position: fixed;
+    inset: 0;
+    z-index: 1070;
+    background: transparent;
+}
+
+.hosts-file-filter-toggle {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 0.35rem;
+    width: 100%;
+    padding: 0.25rem 0.55rem;
+    font-size: 0.875rem;
+    line-height: 1.5;
+    text-align: left;
+    color: var(--bs-body-color);
+    background-color: var(--bs-body-bg);
+    border: 1px solid var(--bs-border-color);
+    border-radius: var(--bs-border-radius-sm);
+    transition: border-color 0.12s ease, box-shadow 0.12s ease;
+}
+
+.hosts-file-filter-toggle:hover {
+    border-color: #bfc7d4;
+}
+
+.hosts-file-filter-wrap--open .hosts-file-filter-toggle {
+    border-color: #86b7fe;
+    box-shadow: 0 0 0 0.2rem rgba(13, 110, 253, 0.2);
+}
+
+.hosts-file-filter-toggle-label {
+    min-width: 0;
+}
+
+.hosts-file-filter-chevron {
+    font-size: 0.75rem;
+    opacity: 0.65;
+    transition: transform 0.15s ease;
+}
+
+.hosts-file-filter-wrap--open .hosts-file-filter-chevron {
+    transform: rotate(180deg);
+}
+
+.hosts-file-filter-panel {
+    position: absolute;
+    top: calc(100% + 4px);
+    right: 0;
+    left: auto;
+    min-width: 100%;
+    width: max-content;
+    max-width: min(26rem, 92vw);
+    max-height: min(22rem, 55vh);
+    overflow-x: hidden;
+    overflow-y: auto;
+    z-index: 1085;
+    padding: 0.35rem;
+    background: var(--bs-body-bg, #fff);
+    border: 1px solid var(--bs-border-color, #e2e8f0);
+    border-radius: 10px;
+}
+
+.hosts-file-filter-option {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 0.65rem;
+    width: 100%;
+    padding: 0.4rem 0.55rem;
+    margin: 0;
+    font-size: 0.8125rem;
+    line-height: 1.35;
+    text-align: left;
+    color: #1e293b;
+    background: transparent;
+    border: none;
+    border-radius: 6px;
+    cursor: pointer;
+}
+
+.hosts-file-filter-option:hover {
+    background: rgba(15, 23, 42, 0.06);
+}
+
+.hosts-file-filter-option--active {
+    background: rgba(13, 110, 253, 0.12);
+    font-weight: 600;
+}
+
+.hosts-file-filter-option--active:hover {
+    background: rgba(13, 110, 253, 0.18);
+}
+
+.hosts-file-filter-option--all {
+    margin-bottom: 0.25rem;
+    border: 1px solid #e7ebf0;
+    background: linear-gradient(180deg, #fbfcfe 0%, #f4f6f9 100%);
+}
+
+.hosts-file-filter-option-main {
+    flex: 1 1 0%;
+    min-width: 0;
+}
+
+/* Full path when width allows; when truncated, keep the end (usually the filename) visible. Full path in title for hover. */
+.hosts-file-filter-path {
+    display: block;
+    overflow: hidden;
+    white-space: nowrap;
+    text-overflow: ellipsis;
+    direction: rtl;
+    text-align: left;
+    unicode-bidi: plaintext;
+}
+
+.hosts-file-filter-count {
+    flex-shrink: 0;
+    padding: 0.1rem 0.45rem;
+    font-size: 0.7rem;
+    font-weight: 600;
+    font-variant-numeric: tabular-nums;
+    line-height: 1.3;
+    color: #475569;
+    background: rgba(15, 23, 42, 0.06);
+    border-radius: 999px;
+}
+
+.hosts-file-filter-option--active .hosts-file-filter-count {
+    color: #0d47a1;
+    background: rgba(13, 110, 253, 0.2);
+}
+
+.hosts-file-filter-group {
+    margin-top: 0.35rem;
+    padding: 0.3rem 0.35rem 0.45rem;
+    border-radius: 8px;
+    border: 1px solid rgba(15, 23, 42, 0.08);
+}
+
+.hosts-file-filter-group:first-of-type {
+    margin-top: 0;
+}
+
+.hosts-file-filter-group--managed {
+    background: linear-gradient(180deg, #e8f4fd 0%, #dceef9 100%);
+    border-color: #b8d4ee;
+}
+
+.hosts-file-filter-group--system {
+    background: linear-gradient(180deg, #f1f5f9 0%, #e8edf3 100%);
+    border-color: #cbd5e1;
+}
+
+.hosts-file-filter-group--addn {
+    background: linear-gradient(180deg, #fff8e6 0%, #fff0cc 100%);
+    border-color: #e9d48a;
+}
+
+.hosts-file-filter-group--hostsdir {
+    background: linear-gradient(180deg, #ecfdf3 0%, #dff6e8 100%);
+    border-color: #a7e3c0;
+}
+
+.hosts-file-filter-group--other {
+    background: #f8fafc;
+}
+
+.hosts-file-filter-group-header {
+    padding: 0.2rem 0.35rem 0.45rem;
+    font-size: 0.65rem;
+    font-weight: 700;
+    letter-spacing: 0.04em;
+    text-transform: uppercase;
+    color: #334155;
+    border-bottom: 1px solid rgba(15, 23, 42, 0.08);
+    margin-bottom: 0.15rem;
 }
 
 .hosts-toolbar-select {
@@ -161,13 +366,31 @@
 .hosts-group-header__path-row {
     display: flex;
     flex-wrap: wrap;
-    align-items: flex-end;
+    align-items: center;
     justify-content: space-between;
     gap: 0.5rem 0.75rem;
     width: 100%;
     min-width: 0;
 }
 
+/* Fixed column for actions avoids path/subtitle reflow when buttons show or hide. */
+.hosts-group-header__path-row--with-managed-actions {
+    display: grid;
+    grid-template-columns: minmax(0, 1fr) var(--hosts-managed-actions-col, 9.75rem);
+    align-items: center;
+    column-gap: 0.5rem;
+}
+
+.hosts-group-header__path-row--with-managed-actions .hosts-group-header__path {
+    flex: unset;
+    min-width: 0;
+}
+
+.hosts-group-header__path-row--with-managed-actions .hosts-group-header__managed-actions {
+    margin-left: 0;
+    justify-self: end;
+}
+
 .hosts-group-header__path {
     display: flex;
     flex-wrap: wrap;
@@ -180,65 +403,60 @@
 
 .hosts-group-header__managed-actions {
     flex: 0 0 auto;
-    align-self: flex-end;
+    align-self: center;
     margin-left: auto;
     display: inline-flex;
     align-items: center;
-    gap: 0.4rem;
+    justify-content: flex-end;
-    min-height: 2.35rem;
+    gap: 0.28rem;
-    padding: 0.25rem;
+    min-height: 1.65rem;
+    max-width: 100%;
+    padding: 0.18rem;
     border: 1px solid rgba(148, 163, 184, 0.26);
     border-radius: 999px;
     background: linear-gradient(180deg, rgba(255, 255, 255, 0.96) 0%, rgba(248, 250, 252, 0.94) 100%);
-    box-shadow: 0 12px 24px -20px rgba(15, 23, 42, 0.45);
+    box-shadow: 0 8px 18px -16px rgba(15, 23, 42, 0.4);
     backdrop-filter: blur(10px);
-    transform-origin: top right;
+    transition: opacity 160ms ease, border-color 160ms ease, box-shadow 160ms ease, background 160ms ease;
-    transition: opacity 180ms ease, transform 180ms ease, max-width 200ms ease, padding 180ms ease, border-color 180ms ease, box-shadow 180ms ease;
     overflow: hidden;
 }
 
 .hosts-group-header__managed-actions--visible {
     opacity: 1;
-    transform: translateY(0) scale(1);
-    max-width: 16rem;
 }
 
 .hosts-group-header__managed-actions--hidden {
     opacity: 0;
-    transform: translateY(-4px) scale(0.96);
-    max-width: 0;
-    padding-left: 0;
-    padding-right: 0;
     border-color: transparent;
     box-shadow: none;
+    background: transparent;
     pointer-events: none;
 }
 
 .hosts-managed-action-btn {
     display: inline-flex;
     align-items: center;
-    gap: 0.4rem;
+    gap: 0.3rem;
-    min-height: 1.9rem;
+    min-height: 1.28rem;
-    padding: 0.38rem 0.78rem;
+    padding: 0.22rem 0.52rem;
     border: 1px solid transparent;
     border-radius: 999px;
-    font-size: 0.84rem;
+    font-size: 0.75rem;
     font-weight: 600;
     letter-spacing: 0.01em;
     line-height: 1;
     box-shadow: none;
-    transition: transform 140ms ease, box-shadow 140ms ease, background-color 140ms ease, border-color 140ms ease, color 140ms ease;
+    transition: transform 120ms ease, box-shadow 120ms ease, background-color 120ms ease, border-color 120ms ease, color 120ms ease;
-    animation: hosts-managed-action-enter 180ms ease;
 }
 
 .hosts-managed-action-btn i {
-    font-size: 0.85rem;
+    font-size: 0.78rem;
 }
 
 .hosts-managed-action-btn:hover,
 .hosts-managed-action-btn:focus-visible {
-    transform: translateY(-1px);
+    transform: translateY(-0.5px);
-    box-shadow: 0 10px 18px -14px rgba(15, 23, 42, 0.55);
+    box-shadow: 0 6px 14px -12px rgba(15, 23, 42, 0.5);
 }
 
 .hosts-managed-action-btn:active {
@@ -285,18 +503,6 @@
     border-color: rgba(239, 68, 68, 0.42);
 }
 
-@keyframes hosts-managed-action-enter {
-    from {
-        opacity: 0;
-        transform: translateY(-4px) scale(0.96);
-    }
-
-    to {
-        opacity: 1;
-        transform: translateY(0) scale(1);
-    }
-}
-
 .hosts-group-header__badge {
     flex-shrink: 0;
 }
@@ -382,14 +588,23 @@
 }
 
 @media (max-width: 640.98px) {
+    .hosts-group-header__path-row--with-managed-actions {
+        --hosts-managed-actions-col: 9rem;
+    }
+
     .hosts-group-header__managed-actions {
-        gap: 0.3rem;
+        gap: 0.22rem;
-        min-height: 2.2rem;
+        min-height: 1.55rem;
+        padding: 0.15rem;
     }
 
     .hosts-managed-action-btn {
-        padding: 0.34rem 0.68rem;
+        padding: 0.2rem 0.45rem;
-        font-size: 0.8rem;
+        font-size: 0.72rem;
+    }
+
+    .hosts-managed-action-btn i {
+        font-size: 0.74rem;
     }
 }
 
@@ -419,10 +634,16 @@
         border-radius: 12px;
     }
 
+    .hosts-toolbar-fields {
+        flex-wrap: wrap;
+    }
+
     .hosts-toolbar-search,
+    .hosts-file-filter-wrap,
     .hosts-toolbar-select {
         min-width: 0;
         max-width: none;
+        flex: 1 1 100%;
         width: 100%;
     }
 

src/DnsmasqWebUI/Infrastructure/Services/Dnsmasq/Hosts/HostsPageProjectionService.cs

@@ -25,6 +25,12 @@ public sealed class HostsPageProjectionService : IHostsPageProjectionService
         if (query.SourceKindFilter is { } sk)
             filtered = filtered.Where(r => r.SourceKind == sk);
 
+        if (!string.IsNullOrWhiteSpace(query.SourcePathFilter))
+        {
+            var path = query.SourcePathFilter.Trim();
+            filtered = filtered.Where(r => string.Equals(r.SourcePath, path, StringComparison.OrdinalIgnoreCase));
+        }
+
         if (query.EditableFilter is { } ed)
             filtered = filtered.Where(r => r.IsEditable == ed);
 

src/DnsmasqWebUI/Models/Hosts/HostsFileFilterMenuModels.cs

@@ -0,0 +1,10 @@
+namespace DnsmasqWebUI.Models.Hosts;
+
+/// <summary>One hosts file row in the filter menu (path, short name, non-comment line count).</summary>
+public sealed record HostsFileFilterMenuItem(string Path, string FileName, int RecordCount);
+
+/// <summary>A source-kind section in the hosts file filter menu.</summary>
+public sealed record HostsFileFilterMenuGroup(
+    HostsRowSourceKind SourceKind,
+    string Title,
+    IReadOnlyList<HostsFileFilterMenuItem> Files);

src/DnsmasqWebUI/Models/Hosts/HostsPageUi.cs

@@ -23,5 +23,7 @@ public sealed record HostsPageQueryState(
     HostsSortMode Sort,
     bool Descending,
     HostsRowSourceKind? SourceKindFilter,
+    /// <summary>When set, only rows whose <see cref="HostsPageRow.SourcePath"/> matches (ordinal-ignore-case).</summary>
+    string? SourcePathFilter,
     bool? EditableFilter,
     bool? ActiveFilter);

src/DnsmasqWebUI/Models/Hosts/HostsSourcePathDisplay.cs

@@ -0,0 +1,81 @@
+namespace DnsmasqWebUI.Models.Hosts;
+
+/// <summary>Labels for hosts <see cref="HostsPageRow.SourcePath"/> in UI (e.g. file filter dropdown).</summary>
+public static class HostsSourcePathDisplay
+{
+    public static string FormatOptionLabel(string path)
+    {
+        if (string.IsNullOrWhiteSpace(path))
+            return path;
+
+        var trimmed = path.TrimEnd(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar);
+        var name = Path.GetFileName(trimmed);
+        return string.IsNullOrEmpty(name) ? path : name;
+    }
+
+    /// <summary>
+    /// Builds grouped menu data: paths grouped by <see cref="HostsRowSourceKind"/> with per-file record counts
+    /// (non-comment lines). Ensures <paramref name="managedHostsPathAlwaysShow"/> appears even when there are no managed rows yet.
+    /// </summary>
+    public static IReadOnlyList<HostsFileFilterMenuGroup> BuildFileFilterMenuGroups(
+        IReadOnlyList<HostsPageRow> rows,
+        string? managedHostsPathAlwaysShow)
+    {
+        var byPath = rows
+            .Where(r => !string.IsNullOrWhiteSpace(r.SourcePath))
+            .GroupBy(r => r.SourcePath.Trim(), StringComparer.OrdinalIgnoreCase)
+            .Select(g => (
+                Path: g.Key,
+                Kind: g.First().SourceKind,
+                Count: g.Count(r => !r.IsComment)))
+            .ToList();
+
+        var managedTrim = managedHostsPathAlwaysShow?.Trim();
+        if (!string.IsNullOrEmpty(managedTrim)
+            && !byPath.Any(e => string.Equals(e.Path, managedTrim, StringComparison.OrdinalIgnoreCase)))
+            byPath.Add((managedTrim, HostsRowSourceKind.Managed, 0));
+
+        return byPath
+            .GroupBy(e => e.Kind)
+            .OrderBy(g => SourceKindOrder(g.Key))
+            .Select(g =>
+            {
+                var files = g.OrderBy(e => e.Path, StringComparer.OrdinalIgnoreCase)
+                    .Select(e => new HostsFileFilterMenuItem(e.Path, FormatOptionLabel(e.Path), e.Count))
+                    .ToList();
+                return new HostsFileFilterMenuGroup(
+                    g.Key,
+                    GroupMenuTitle(g.Key),
+                    files);
+            })
+            .ToList();
+    }
+
+    public static string GroupMenuTitle(HostsRowSourceKind kind) => kind switch
+    {
+        HostsRowSourceKind.Managed => "Managed hosts",
+        HostsRowSourceKind.SystemHosts => "System hosts",
+        HostsRowSourceKind.AddnHosts => "Additional hosts",
+        HostsRowSourceKind.Hostsdir => "Hosts directory",
+        _ => "Hosts files"
+    };
+
+    public static string GroupSummaryPrefix(HostsRowSourceKind kind) => kind switch
+    {
+        HostsRowSourceKind.Managed => "Managed",
+        HostsRowSourceKind.SystemHosts => "System",
+        HostsRowSourceKind.AddnHosts => "Additional",
+        HostsRowSourceKind.Hostsdir => "Hosts dir",
+        _ => "Hosts"
+    };
+
+    private static int SourceKindOrder(HostsRowSourceKind kind) => kind switch
+    {
+        HostsRowSourceKind.Managed => 0,
+        HostsRowSourceKind.SystemHosts => 1,
+        HostsRowSourceKind.AddnHosts => 2,
+        HostsRowSourceKind.Hostsdir => 3,
+        _ => 99
+    };
+
+}