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fix: trap focus inside Dialog, AlertDialog, Sheet and Drawer #64

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Merged
Shewart merged 4 commits into from
Oct 18, 2026
Merged

fix: trap focus inside Dialog, AlertDialog, Sheet and Drawer #64

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cbee7db
fix: trap focus inside Dialog, AlertDialog, Sheet and Drawer
Shewart Oct 17, 2026
7aeba79
fix: focus the legacy Sheet and Drawer panels, trap focus and close o…
Shewart Oct 17, 2026
6291206
test: cover the overlay focus trap
Shewart Oct 17, 2026
e3541fb
Merge branch 'main' into fix/overlay-focus-trap
Shewart Oct 17, 2026
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53 changes: 53 additions & 0 deletions ShellUI.Tests/PackageBehaviorTests.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -63,6 +63,59 @@ public void Dropdown_ClosesOnEscapeButNotOnOtherKeys()
Assert.Equal(new[] { false }, changes);
}

[Fact]
public void DialogContent_TrapsFocusWhileOpenAndReleasesItOnClose()
{
using var ctx = new BunitContext();
ctx.JSInterop.Mode = JSRuntimeMode.Loose;

var dialog = ctx.Render<Dialog>(p => p
.Add(c => c.Open, true)
.AddChildContent<DialogContent>(c => c.AddChildContent("Body")));

var trap = ctx.JSInterop.VerifyInvoke("ShellUI.trapFocus");
ctx.JSInterop.VerifyNotInvoke("ShellUI.releaseFocus");

dialog.Render(p => p.Add(c => c.Open, false));

var release = ctx.JSInterop.VerifyInvoke("ShellUI.releaseFocus");
Assert.Equal(trap.Arguments[0], release.Arguments[0]);
}

[Fact]
public void SheetContent_TrapsFocusWhileOpen()
{
using var ctx = new BunitContext();
ctx.JSInterop.Mode = JSRuntimeMode.Loose;

ctx.Render<Sheet>(p => p
.Add(c => c.Open, true)
.AddChildContent<SheetContent>(c => c.AddChildContent("Body")));

ctx.JSInterop.VerifyInvoke("ShellUI.trapFocus");
}

[Fact]
public void LegacySheet_TrapsFocusAndReleasesItWhenEscapeCloses()
{
using var ctx = new BunitContext();
ctx.JSInterop.Mode = JSRuntimeMode.Loose;
bool? open = null;

var sheet = ctx.Render<Sheet>(p => p
.Add(c => c.Open, true)
.Add(c => c.Title, "Settings")
.Add(c => c.OpenChanged, EventCallback.Factory.Create<bool>(this, v => open = v))
.AddChildContent("Body"));

ctx.JSInterop.VerifyInvoke("ShellUI.trapFocus");

sheet.Find("[role=dialog]").KeyDown(new KeyboardEventArgs { Key = "Escape" });

Assert.False(open);
ctx.JSInterop.VerifyInvoke("ShellUI.releaseFocus");
}

[Fact]
public void TimePicker_ShowsASetValue()
{
Expand Down
17 changes: 16 additions & 1 deletion src/ShellUI.Components/Components/AlertDialogContent.razor
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,8 @@
private bool _isLocked;
private bool _focused;
private ElementReference _content;
private readonly string _trapId = Guid.NewGuid().ToString("N");
private bool _trapped;

// Escape dismisses an alert dialog as Cancel; the backdrop does not.
private async Task OnKeyDownAsync(KeyboardEventArgs e)
Expand All @@ -34,9 +36,14 @@
if (isOpen && !_focused)
{
_focused = true;
try { await JS.InvokeVoidAsync("ShellUI.trapFocus", _trapId, _content); _trapped = true; } catch { }
try { await _content.FocusAsync(); } catch (InvalidOperationException) { }
}
else if (!isOpen) _focused = false;
else if (!isOpen)
{
_focused = false;
await ReleaseFocusAsync();
}

var shouldBeLocked = Parent?.IsOpen == true;
if (shouldBeLocked && !_isLocked)
Expand All @@ -49,8 +56,16 @@
}
}

private async Task ReleaseFocusAsync()
{
if (!_trapped) return;
_trapped = false;
try { await JS.InvokeVoidAsync("ShellUI.releaseFocus", _trapId); } catch { }
}

public async ValueTask DisposeAsync()
{
await ReleaseFocusAsync();
if (_isLocked)
{
try { await JS.InvokeVoidAsync("ShellUI.unlockBodyScroll"); } catch { }
Expand Down
17 changes: 16 additions & 1 deletion src/ShellUI.Components/Components/DialogContent.razor
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,8 @@
private bool _isLocked;
private bool _focused;
private ElementReference _content;
private readonly string _trapId = Guid.NewGuid().ToString("N");
private bool _trapped;

private async Task Close()
{
Expand All @@ -45,9 +47,14 @@
if (isOpen && !_focused)
{
_focused = true;
try { await JS.InvokeVoidAsync("ShellUI.trapFocus", _trapId, _content); _trapped = true; } catch { }
try { await _content.FocusAsync(); } catch (InvalidOperationException) { }
}
else if (!isOpen) _focused = false;
else if (!isOpen)
{
_focused = false;
await ReleaseFocusAsync();
}

var shouldBeLocked = Dialog?.Open == true;
if (shouldBeLocked && !_isLocked)
Expand All @@ -60,8 +67,16 @@
}
}

private async Task ReleaseFocusAsync()
{
if (!_trapped) return;
_trapped = false;
try { await JS.InvokeVoidAsync("ShellUI.releaseFocus", _trapId); } catch { }
}

public async ValueTask DisposeAsync()
{
await ReleaseFocusAsync();
if (_isLocked)
{
try { await JS.InvokeVoidAsync("ShellUI.unlockBodyScroll"); } catch { }
Expand Down
40 changes: 39 additions & 1 deletion src/ShellUI.Components/Components/Drawer.razor
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,4 +1,7 @@
@namespace ShellUI.Components
@using Microsoft.JSInterop
@implements IAsyncDisposable
@inject IJSRuntime JS

@if (UseCompositional)
{
Expand All @@ -9,7 +12,7 @@
else if (Open)
{
<div class="fixed inset-0 z-50 bg-black/80 animate-in fade-in-0" @onclick="Close"></div>
<div class="@DrawerVariants.Get(Side, Class)" @onclick:stopPropagation="true" @attributes="AdditionalAttributes">
<div @ref="_panel" tabindex="-1" role="dialog" aria-modal="true" @onkeydown="OnPanelKeyDownAsync" class="outline-none @DrawerVariants.Get(Side, Class)" @onclick:stopPropagation="true" @attributes="AdditionalAttributes">
<div class="mx-auto mt-4 h-2 w-[100px] rounded-full bg-muted"></div>
<div class="grid gap-1.5 p-4 text-center sm:text-left">
@if (!string.IsNullOrEmpty(Title))
Expand Down Expand Up @@ -55,4 +58,39 @@ else if (Open)
{
if (Open != value) { Open = value; await OpenChanged.InvokeAsync(Open); StateHasChanged(); }
}

private ElementReference _panel;
private readonly string _trapId = Guid.NewGuid().ToString("N");
private bool _focused;
private bool _trapped;

private async Task OnPanelKeyDownAsync(KeyboardEventArgs e)
{
if (e.Key == "Escape") await Close();
}

protected override async Task OnAfterRenderAsync(bool firstRender)
{
var panelOpen = Open && !UseCompositional;
if (panelOpen && !_focused)
{
_focused = true;
try { await JS.InvokeVoidAsync("ShellUI.trapFocus", _trapId, _panel); _trapped = true; } catch { }
try { await _panel.FocusAsync(); } catch (InvalidOperationException) { }
}
else if (!panelOpen)
{
_focused = false;
await ReleaseFocusAsync();
}
}

private async Task ReleaseFocusAsync()
{
if (!_trapped) return;
_trapped = false;
try { await JS.InvokeVoidAsync("ShellUI.releaseFocus", _trapId); } catch { }
}

public async ValueTask DisposeAsync() => await ReleaseFocusAsync();
}
17 changes: 16 additions & 1 deletion src/ShellUI.Components/Components/DrawerContent.razor
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,8 @@
private bool _isLocked;
private bool _focused;
private ElementReference _content;
private readonly string _trapId = Guid.NewGuid().ToString("N");
private bool _trapped;

private async Task Close()
{
Expand All @@ -41,9 +43,14 @@
if (isOpen && !_focused)
{
_focused = true;
try { await JS.InvokeVoidAsync("ShellUI.trapFocus", _trapId, _content); _trapped = true; } catch { }
try { await _content.FocusAsync(); } catch (InvalidOperationException) { }
}
else if (!isOpen) _focused = false;
else if (!isOpen)
{
_focused = false;
await ReleaseFocusAsync();
}

var shouldBeLocked = Parent?.Open == true;
if (shouldBeLocked && !_isLocked)
Expand All @@ -56,8 +63,16 @@
}
}

private async Task ReleaseFocusAsync()
{
if (!_trapped) return;
_trapped = false;
try { await JS.InvokeVoidAsync("ShellUI.releaseFocus", _trapId); } catch { }
}

public async ValueTask DisposeAsync()
{
await ReleaseFocusAsync();
if (_isLocked)
{
try { await JS.InvokeVoidAsync("ShellUI.unlockBodyScroll"); } catch { }
Expand Down
40 changes: 39 additions & 1 deletion src/ShellUI.Components/Components/Sheet.razor
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,4 +1,7 @@
@namespace ShellUI.Components
@using Microsoft.JSInterop
@implements IAsyncDisposable
@inject IJSRuntime JS

@if (UseCompositional)
{
Expand All @@ -9,7 +12,7 @@
else if (Open)
{
<div class="fixed inset-0 z-50 bg-background/80 backdrop-blur-sm animate-in fade-in-0" @onclick="Close"></div>
<div class="@SheetVariants.Get(Side, Class)" @onclick:stopPropagation="true" @attributes="AdditionalAttributes">
<div @ref="_panel" tabindex="-1" role="dialog" aria-modal="true" @onkeydown="OnPanelKeyDownAsync" class="outline-none @SheetVariants.Get(Side, Class)" @onclick:stopPropagation="true" @attributes="AdditionalAttributes">
<div class="flex flex-col space-y-2">
<div class="flex items-center justify-between">
@if (!string.IsNullOrEmpty(Title))
Expand Down Expand Up @@ -63,4 +66,39 @@ else if (Open)
{
if (Open != value) { Open = value; await OpenChanged.InvokeAsync(Open); StateHasChanged(); }
}

private ElementReference _panel;
private readonly string _trapId = Guid.NewGuid().ToString("N");
private bool _focused;
private bool _trapped;

private async Task OnPanelKeyDownAsync(KeyboardEventArgs e)
{
if (e.Key == "Escape") await Close();
}

protected override async Task OnAfterRenderAsync(bool firstRender)
{
var panelOpen = Open && !UseCompositional;
if (panelOpen && !_focused)
{
_focused = true;
try { await JS.InvokeVoidAsync("ShellUI.trapFocus", _trapId, _panel); _trapped = true; } catch { }
try { await _panel.FocusAsync(); } catch (InvalidOperationException) { }
}
else if (!panelOpen)
{
_focused = false;
await ReleaseFocusAsync();
}
}

private async Task ReleaseFocusAsync()
{
if (!_trapped) return;
_trapped = false;
try { await JS.InvokeVoidAsync("ShellUI.releaseFocus", _trapId); } catch { }
}

public async ValueTask DisposeAsync() => await ReleaseFocusAsync();
}
17 changes: 16 additions & 1 deletion src/ShellUI.Components/Components/SheetContent.razor
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,8 @@
private bool _isLocked;
private bool _focused;
private ElementReference _content;
private readonly string _trapId = Guid.NewGuid().ToString("N");
private bool _trapped;

private async Task Close()
{
Expand All @@ -40,9 +42,14 @@
if (isOpen && !_focused)
{
_focused = true;
try { await JS.InvokeVoidAsync("ShellUI.trapFocus", _trapId, _content); _trapped = true; } catch { }
try { await _content.FocusAsync(); } catch (InvalidOperationException) { }
}
else if (!isOpen) _focused = false;
else if (!isOpen)
{
_focused = false;
await ReleaseFocusAsync();
}

var shouldBeLocked = Parent?.Open == true;
if (shouldBeLocked && !_isLocked)
Expand All @@ -55,8 +62,16 @@
}
}

private async Task ReleaseFocusAsync()
{
if (!_trapped) return;
_trapped = false;
try { await JS.InvokeVoidAsync("ShellUI.releaseFocus", _trapId); } catch { }
}

public async ValueTask DisposeAsync()
{
await ReleaseFocusAsync();
if (_isLocked)
{
try { await JS.InvokeVoidAsync("ShellUI.unlockBodyScroll"); } catch { }
Expand Down
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