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fix(tooltip): Keep the popup panel as parent while a ToolTip is open - #24592
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When a ToolTip opened, it was added to the popup panel and its parent was then reset to what it was before, which is null for a tooltip set through ToolTipService. Layout invalidations from the tooltip content walk the parent chain to reach the layout root, so they stopped at the tooltip: an Image whose bitmap arrived after the tooltip opened kept its measure-dirty flag and stayed blank until the tooltip was opened again and measured from scratch. The tooltip now stays parented to the popup panel while it is showing and leaves it when it closes. The parent was reset to keep the panel's DataContext from replacing the one the owner provides through ToolTipService.ToolTip, so that value is re-applied after parenting and the owner's DataContextChanged is forwarded while open. Fixes unoplatform#24557
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Copilot review overview
🟡 Changes recommended
Unresolved popup-parenting and DataContext handling issues remain.
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Review effort: Lite
Findings: 2
Open (2)
What changed in this PR
Fixes tooltip image loading by keeping open tooltips attached to the popup panel and preserving owner DataContext behavior.
Changes:
- Updates tooltip popup parenting and data-context forwarding.
- Adds regression coverage for deferred image loading.
| File | Summary |
|---|---|
src/Uno.UI/UI/Xaml/Controls/ToolTip/ToolTip.cs |
Updates popup attachment, detachment, and data-context handling. |
src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml_Controls/Given_ToolTip.cs |
Adds deferred image-loading tooltip coverage. |
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Popup.Child sets the logical parent override, so the public Parent is the popup after the first open and the actual parent must drive the attach. The owner DataContext is read before joining the popup panel, whose own DataContext is inherited on parenting.
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The build 235198 found UI Test snapshots differences: Details
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Xiaoy312
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Xiaoy312
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Thanks for this, it also fixes #24820 (same root cause, ItemsControl content instead of an Image). I compared the DataContext behavior against native WinUI and found two differences from WinUI. Both come from the parenting and DataContext changes.
The same probe code ran on native WinUI (standalone unpackaged app, WinAppSDK 1.7.250606001) and on Uno Skia desktop, with master's ToolTip.cs and with this PR's (eb38bcbb84).
1. The tooltip loses its DataContext on close
The owner's DataContext is set after SetToolTip; the tooltip is then opened and closed twice, and the owner's DataContext changes in between. The tooltip content is a TextBlock bound to {Binding}.
| Step | WinUI | Uno master |
This PR |
|---|---|---|---|
| open #1 | VM1 |
VM1 |
VM1 |
| closed #1 | VM1 (text kept) |
VM1 |
null (text empty) |
closed, owner changes to VM2 |
VM2 |
VM2 |
VM2 |
open #2, owner changes to VM3 |
VM3 |
VM3 |
VM3 |
| closed #2 | VM3 |
VM3 |
null |
DetachFromPopup calls SetParent(null), and changing the parent clears every value inherited from it, DataContext included (DependencyObject.Store Parent setter → CleanupInheritedProperties). Nothing puts it back: the owner only pushes its DataContext when that DataContext changes. So every hover now flips the tooltip's subtree between null and the view model. Bindings re-run, converters are handed null, and an ItemsControl in the tooltip clears and rebuilds its items. WinUI and master keep the DataContext while closed.
Suggested fix: in DetachFromPopup, capture DataContext before SetParent(null) and set it back afterwards at Inheritance precedence, as AttachToPopup does when opening.
2. With ToolTipService.PlacementTarget, the tooltip follows the placement target
The owner's DataContext is Owner and the placement target's is Target.
| Step | WinUI | Uno master |
This PR |
|---|---|---|---|
| open | Owner |
Target |
Target |
owner changes to Owner2 while open |
Owner2 |
Owner2 |
Target |
target changes to Target2 while open |
Owner2 (ignored) |
Owner2 |
Target2 |
| closed | Owner2 |
Owner2 |
null |
WinUI takes the tooltip's DataContext from the owner (ToolTip::SetContainer). The placement target is only used for positioning and flow direction. Uno stores the placement target as the tooltip's _owner (toolTip.SetAnchor(GetPlacementTarget(container) ?? container) in ToolTipService.RegisterToolTip). So master already opens with the wrong DataContext, but after that it follows the real owner. This PR subscribes OnOwnerDataContextChanged to that same _owner. Because the owner's own changes no longer reach a tooltip parented to the popup panel, the tooltip now follows the placement target entirely.
The root cause is older than this PR. But since this PR adds the forwarding, it would help if ToolTip kept the owner separately from the placement anchor, and took its DataContext from the owner (both the "propagate the DC once" on open and the new DataContextChanged forwarding).
3. The tooltip's parents: closer to WinUI
For reference, the parenting change itself moves Uno toward WinUI.
| WinUI | Uno master |
This PR | |
|---|---|---|---|
Open: VisualTreeHelper.GetParent(toolTip) |
popup root (Canvas) |
null |
PopupRoot |
Open: toolTip.Parent |
Popup |
Popup |
Popup |
| Open: walking up from the tooltip's content | ContentPresenter > ToolTip > Canvas > null |
ContentPresenter > ToolTip > null |
ContentPresenter > ToolTip > PopupRoot > XamlIslandRoot > null |
Closed: VisualTreeHelper.GetParent(toolTip) / toolTip.Parent |
null / null |
null / Popup |
null / Popup |
An open WinUI tooltip has the popup root as its visual parent, and so does this PR; master has none, which is the gap behind both #24557 and #24820. One small difference remains in both Uno versions: WinUI clears Popup.Child when the tooltip closes (ToolTip::Close), so Parent goes back to null, while Uno keeps Popup. Nothing here needs to change for this PR.
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For a |
…ver it closed (port) Port of 9d414ec (stacked on unoplatform#24592). As in WinUI's ToolTip::OnIsOpenChanged, the ToolTip tells the service when it has closed, and the service drops it if it is still the current one, so a tooltip closed by a path the service does not drive (its popup closed with the other popups, or the app setting IsOpen) is not kept. 6.8 differences: the call sits after UnsubscribeOwnerDataContextChanged in ToolTip.OnOpenChanged (6.8's shape of unoplatform#24592), and the tests live in Tests/Windows_UI_Xaml_Controls. This branch also carries the unoplatform#25102 port, so the owner is already collected once it unloads; the service-state test is the one that fails without this change here.
The tooltip tests closed their popups in finally but left their owner as the window content, so the visual tree outlived the test.
…platform#25137 after review The unoplatform#24592 tooltip tests reset the window content in finally (ca34dc1). The unoplatform#25137 tests follow e7496a8: compiled on every head and skipped on native WinUI with PlatformCondition instead of #if HAS_UNO, popups closed through the public VisualTreeHelper.GetOpenPopupsForXamlRoot, and a new test for a tooltip whose opening is cancelled during the show delay. The source side of e7496a8 is already on this branch: the ToolTip close notification (3cfe072) and the service-side clears it carries from unoplatform#25102 (800247f).
morning4coffe-dev
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Verified: diff of ToolTip.cs, ToolTipService.cs and Given_ToolTip.cs at head ca34dc1, the review thread (including the WinUI probe tables), and the WinUI source: ToolTip_Partial.cpp SetContainer (L72-87), OpenPopup (L573-611), Close (L666-690); ToolTipService_Partial.cpp RegisterToolTip (L153-154), container resolution on pointer enter (L631-634), unregister (L288-289). Uno side: Popup.WithPopupRoot.cs (L26-30), ToolTipService.Properties.cs (default FrameworkPropertyMetadata). Not built or run. Runtime results are author-reported (Skia desktop only). CI rollup shows no failing checks; no Azure runtime test check appears in the rollup.
Findings (by severity):
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Medium - ToolTip.cs:234-236 and ToolTip.cs:248-250. The owner DataContextChanged handler is subscribed and unsubscribed through GetDataContextOwner(), which reads _container at each call. _container is set in SetContainer (ToolTipService.cs:48) and never cleared; UnregisterToolTip does not call SetContainer(null) (WinUI does, ToolTipService_Partial.cpp:289). If the same ToolTip is registered against another container while it is open, Close unsubscribes the new container and leaves the handler on the old one, so a closed tooltip keeps receiving DataContext writes. Suggested fix: keep the element that was subscribed in a field and unsubscribe from that field.
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Low - ToolTip.cs:194 (SetParent(Popup.PopupPanel)) and ToolTip.cs:215 (SetParent(null)). Popup.Child assignment already adds and removes the child in PopupPanel.Children (Popup.WithPopupRoot.cs:26-30), so these writes appear redundant. Not wrong, but the comments imply they are load-bearing. Either drop them or state what they guard.
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Low - Parity source gap. WinUI's ToolTip has no DataContextChanged subscription (ToolTip_Partial.cpp has no such handler); it snapshots the container DataContext in SetContainer. The forwarding added here (ToolTip.cs:254-259) is what makes owner changes visible while open, and the review probe table reports WinUI doing the same. The parity for that behavior rests on the probe, not on the source. A code comment citing the probe, or the test comment, would make this checkable.
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Note - closed-state DataContext. The PR's "closed tooltip keeps its DataContext" and "owner change while closed reaches it" depend on ToolTipService.ToolTip's default metadata (ValueInheritsDataContext is the default, FrameworkPropertyMetadataOptions.cs:81), not on the forwarding, which is unsubscribed on close. I read this from source; the PR body does not explain it. Worth one sentence in the PR or a code comment.
Not validated by me: runtime behavior of all five new Given_ToolTip tests (author reports Skia desktop pass and fail-before on master); WASM, Android, iOS; the image-load test asset availability on other targets.
The owner's DataContextChanged and ActualThemeChanged were subscribed on open and unsubscribed on close through the container and the anchor, which are read again each time. When the tooltip is set on another element while it is open, both change in between, so closing unsubscribed from the new element and left the handlers on the first one for good: it kept writing its DataContext into the tooltip even after the tooltip was removed from it. Keep the elements that were subscribed and unsubscribe from those.
Since the popup lets go of the tooltip on close, every open assigns Popup.Child afresh, and the popup adds its child to the popup panel and removes it again, which sets and clears the tooltip's parent. The explicit SetParent calls and the guard around the Popup.Child assignment no longer did anything.
The closed tooltip gets its owner's DataContext changes from ToolTipService.ToolTip's default metadata (ValueInheritsDataContext), and the parity of forwarding them while open rests on WinUI's behavior rather than on its source, which has no such handler: the DataContext tests run on native WinUI and pass there. Say both where they apply.
On native WinUI the popup lets go of the tooltip only once the Closed visual transition has played (ToolTip::Close runs when its storyboard completes), so When_Closed_Then_Parent_Cleared failed there right after WaitForIdle. Wait for the parent to clear instead; Uno releases it as soon as the tooltip closes.
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@morning4coffe-dev, by finding:
@Xiaoy312, both DataContext differences from your probe were addressed in 427c457 ( |
AttachToPopup and DetachFromPopup carried the tooltip's DataContext across the parent change by reading DataContext, the effective value, and writing it back at Inheritance precedence. A DataContext set or bound on the tooltip itself was therefore copied into the layer the owner provides: clearing a local value left it behind, and a binding re-evaluated against its own result. Read the inherited value instead.
…at was subscribed (port) Port of the latest unoplatform#24592 round (0994593, bd13144, 94e4f41, d62ceb9 and b825e58 on top of ca34dc1): - Closing unsubscribes from the elements that were subscribed on open, kept in _themeSource and _dataContextSource, instead of reading the anchor and the container again, which change when the tooltip is set on another element while it is open. - AttachToPopup and DetachFromPopup carry the inherited DataContext only, so a DataContext set or bound on the tooltip itself is not copied into the layer the owner provides. - Popup.Child parents the tooltip: the explicit SetParent calls and the guard around the assignment are gone. - The tests from those commits, the [Bindable] view model they use, and the comments. 6.8 differences: - The theme subscription is still behind UNO_HAS_ENHANCED_LIFECYCLE, and the DataContext forwarding has its own unconditional pair (47830b3), so _themeSource sits in the gated pair and _dataContextSource in the other. - 6.8 has ReadInheritedValueOrDefaultValue on DependencyObjectStore only, so it is called through IDependencyObjectStoreProvider, as Control does. - Dropping SetParent holds on 6.8 too: Popup.Child goes through the same OnChildChangedPartialNative, and PopupPanel.Children.Add and Remove set and clear the parent (UIElement.AddChild/RemoveChild on Skia and WASM, BindableView on Android). - The tests live in Tests/Windows_UI_Xaml_Controls. The hover helpers keep GetAbsoluteBoundsRect: 7c16adc only fixes the WinAppSDK test build. unoplatform#25137 (c43992e) carries no source change beyond the earlier port: ToolTipService.cs already matches it.
MartinZikmund
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GitHub Issue: closes #24557, closes #24820
PR Type:
🐞 Bugfix
What changed? 🚀
On Skia, an
Imageinside an openToolTipstayed blank when its bitmap arrived after the tooltip opened, and only showed the next time the tooltip opened.The bitmap is applied during measure, and
Image.InvalidateMeasure()reaches the layout root by walking the parent chain. When aToolTipopens,AttachToPopupadded it to the popup panel and then reset its parent to the previous value, which isnullfor a tooltip set throughToolTipService. The dirty path therefore stopped at the tooltip: the image kept its measure-dirty flag, the popup panel was never flagged, and no layout pass reached the image until the tooltip was opened again and measured from scratch. Verified by dumping the chain at the point of failure:The parent was reset to keep the popup panel's own
DataContextfrom replacing the one the owner provides throughToolTipService.ToolTip(that attached property hasValueInheritsDataContext, which no longer forwards changes once the value is parented elsewhere).The tooltip now stays parented to the popup panel while it is showing and is detached again when it closes, so the closed state is unchanged. To keep the DataContext behavior:
DataContextChangedis forwarded to the tooltip while it is open, alongside the existingActualThemeChangedsubscription. The elements that were subscribed are kept, so closing unsubscribes from those even if the tooltip has been set on another element in the meantime.While closed, the tooltip needs no forwarding: it is again a value of the owner's
ToolTipService.ToolTip, whose default metadata (ValueInheritsDataContext) pushes the owner's DataContext changes to it. WinUI'sToolTiphas noDataContextChangedhandler; that an open WinUI tooltip follows its owner's changes comes from the WinUI probe in the review, and the two DataContext tests below pass on native WinUI as well.The same broken parent chain is behind #24820, where an
ItemsControlinside the tooltip creates its containers after the first measure and the tooltip stays an empty border on its first open.DataContext follow-ups
Comparing against native WinUI surfaced two DataContext differences (see the review discussion), both now addressed:
nullafter every hover. The value is now kept across the detach, as on WinUI and on master. Only the inherited value is carried across, so a DataContext set or bound on the tooltip itself stays on top of it and doesn't leak into it.ToolTipServicehanded the tooltip a single element (thePlacementTargetwhen set, else the owner) for both positioning and DataContext, so a tooltip with a placement target opened with the target's DataContext and, with the forwarding added here, followed it entirely. The tooltip now keeps the owner (the element the tooltip is set on) separately from the placement anchor and takes its DataContext from the owner, asToolTip::SetContainerdoes in WinUI. The placement target only positions the tooltip.The popup also releases the tooltip when it closes, as
ToolTip::Closedoes in WinUI, soParentisnullwhile closed instead of thePopup. Assigning and clearingPopup.Childis what sets and clears the tooltip's parent, so the tooltip no longer callsSetParentitself.Tests
New
Given_ToolTipruntime tests:When_Image_Source_Loads_While_Open([Regression][Skia] Image inside an open ToolTip stays blank when its source loads after the ToolTip opened #24557)When_Content_Realizes_On_Load_Then_Measured_On_First_Open([Skia] ToolTip shows an empty border on first open when its content realizes after load (e.g. ItemsControl) #24820, from the issue)When_Closed_Then_DataContext_Kept(passes on master, fails on the first revision of this PR)When_PlacementTarget_Then_DataContext_From_OwnerWhen_Closed_Then_Parent_ClearedWhen_Moved_To_Another_Owner_While_Open_Then_Former_Owner_Not_Followed(fails when closing unsubscribes through the current container)When_Local_DataContext_Cleared_After_Close_Then_Not_KeptandWhen_DataContext_Bound_Then_Bound_To_Owner_Across_Close(fail when the effective DataContext, not the inherited one, is carried across the parent change)The first five fail on master's
ToolTip(except as noted) and pass with this PR; their expected values mirror the native WinUI probe results posted in the review, and all of them except the bound-DataContext test pass on native WinUI too (Given_ToolTiprun on the WinAppSDK SamplesApp head; that test is excluded there, since WinUI writes the owner's DataContext over a binding on the tooltip when the owner's changes;When_Closed_Then_Parent_Clearedwaits for the parent to clear, since WinUI's popup releases the tooltip only after the Closed transition). Validation on Skia desktop:Given_ToolTip,Given_Slider,Given_Image,Given_Popup,Given_ElementTheme,Given_Control,Given_DragView,Given_FrameworkElement_And_Leak,Given_PropertyPathListener,KeyboardAcceleratorTestsandTabViewTestsall pass (371 tests, 11 skipped), including the four DataContext-tracking tooltip tests that guard the reason the parent used to be reset.PR Checklist ✅
Screenshots Compare Test Runresults.