Combo box popups and tooltips reopen as background windows under GNOME Wayland/Xwayland

[danjboyd]

Summary

Under GNOME on a Wayland session, GNUstep combo box dropdowns and native tooltips can appear once and then fail to reappear on subsequent attempts.

The root cause appears to be that these popup-style panels are shown as independent top-level windows rather than transient children of their owning window.

Environment

• Debian 13
• GNOME session on Wayland
• GNUstep apps running under Xwayland
• libs-gui current master

Observed behavior

Combo boxes

• The first combo box dropdown often appears.
• On the second attempt, the dropdown does not appear.
• GNOME shows a notification like "Window" is ready, which suggests the popup is being treated as a separate top-level window.

Tooltips

• Native GNUstep tooltips show the first time.
• Subsequent tooltip displays may fail in the same way.

Expected behavior

Combo box dropdowns and tooltips should remain associated with their owning window and reliably reopen in the foreground instead of being managed as unrelated top-level windows.

Notes from investigation

This appears to be a libs-gui issue.

The issue was resolved locally by changing libs-gui so the combo popup window and tooltip window are attached to their owning window as child/transient windows before being shown, and detached when dismissed.

The relevant areas are:

• Source/NSComboBoxCell.m
• Source/GSToolTips.m

The working patch makes these popup windows follow the same general ownership model already used for menu windows.

Proposed fix

Before showing these popup panels:

• attach the combo popup window to the control's window
• attach the shared tooltip window to the view's window

When the popup is dismissed:

• detach it again

This allows the window manager to keep these popup windows associated with the owning application window.

Patch

I am attaching the working patch in a follow-up comment.

[danjboyd]

Patch that fixes this locally:

diff --git a/Source/GSToolTips.m b/Source/GSToolTips.m
index c2b5aee3c..3c0d98597 100644
--- a/Source/GSToolTips.m
+++ b/Source/GSToolTips.m
@@ -226,6 +226,34 @@ static BOOL   isOpening = NO;
 static NSSize		offset;
 static BOOL		restoreMouseMoved;
 
+static void
+GSSyncToolTipParentWindow(NSWindow *toolTipWindow, NSWindow *ownerWindow)
+{
+  NSWindow *parentWindow = [toolTipWindow parentWindow];
+
+  if (parentWindow != nil && parentWindow != ownerWindow)
+    {
+      [parentWindow removeChildWindow: toolTipWindow];
+      parentWindow = nil;
+    }
+
+  if (ownerWindow != nil && parentWindow != ownerWindow)
+    {
+      [ownerWindow addChildWindow: toolTipWindow ordered: NSWindowAbove];
+    }
+}
+
+static void
+GSDetachToolTipParentWindow(NSWindow *toolTipWindow)
+{
+  NSWindow *parentWindow = [toolTipWindow parentWindow];
+
+  if (parentWindow != nil)
+    {
+      [parentWindow removeChildWindow: toolTipWindow];
+    }
+}
+
 + (void) initialize
 {
   viewsMap = NSCreateMapTable(NSNonOwnedPointerMapKeyCallBacks,
@@ -567,6 +595,7 @@ static BOOL		restoreMouseMoved;
     {
       [window setFrame: NSZeroRect display: NO];
       [window orderOut:self];
+      GSDetachToolTipParentWindow(window);
     }
   if (restoreMouseMoved == YES)
     {
@@ -695,6 +724,7 @@ static BOOL		restoreMouseMoved;
   isOpening = YES;
   [(GSTTView*)([window contentView]) setText: toolTipText];
   [window setFrame: rect display: NO];
+  GSSyncToolTipParentWindow(window, [view window]);
   [window orderFront: nil];
   isOpening = NO;
 
@@ -702,4 +732,3 @@ static BOOL		restoreMouseMoved;
 }
 
 @end
-
diff --git a/Source/NSComboBoxCell.m b/Source/NSComboBoxCell.m
index cb8e7aefb..0c981a367 100644
--- a/Source/NSComboBoxCell.m
+++ b/Source/NSComboBoxCell.m
@@ -113,6 +113,34 @@ static NSNotificationCenter *nc;
 
 static GSComboWindow *gsWindow = nil;
 
+static void
+GSSyncComboPopupParentWindow(NSWindow *popupWindow, NSWindow *ownerWindow)
+{
+  NSWindow *parentWindow = [popupWindow parentWindow];
+
+  if (parentWindow != nil && parentWindow != ownerWindow)
+    {
+      [parentWindow removeChildWindow: popupWindow];
+      parentWindow = nil;
+    }
+
+  if (ownerWindow != nil && parentWindow != ownerWindow)
+    {
+      [ownerWindow addChildWindow: popupWindow ordered: NSWindowAbove];
+    }
+}
+
+static void
+GSDetachComboPopupParentWindow(NSWindow *popupWindow)
+{
+  NSWindow *parentWindow = [popupWindow parentWindow];
+
+  if (parentWindow != nil)
+    {
+      [parentWindow removeChildWindow: popupWindow];
+    }
+}
+
 @implementation GSComboWindow
 
 + (GSComboWindow *) defaultPopUp
@@ -368,7 +396,8 @@ static GSComboWindow *gsWindow = nil;
   [nc addObserver: self selector: @selector(onWindowEdited:) 
     name: NSWindowDidResizeNotification object: onWindow];
   // End of the code to remove
-  
+
+  GSSyncComboPopupParentWindow(self, onWindow);
   [self orderFront: self];
   [self makeFirstResponder: _tableView];
   [self runLoopWithComboBoxCell: comboBoxCell];
@@ -376,6 +405,7 @@ static GSComboWindow *gsWindow = nil;
   [nc removeObserver: self name: nil object: onWindow];
   
   [self close];
+  GSDetachComboPopupParentWindow(self);
 
   [onWindow makeFirstResponder: [_cell controlView]];
 }