Merge pull request #9042 from mono/jstedfast-debugger-tooltip-show-crash-fix

[Debugger] Make sure tooltip request wasn't cancelled before showing

Author: jstedfast

main/src/addins/MonoDevelop.Debugger/MonoDevelop.Debugger.VSTextView/QuickInfo/DebuggerQuickInfoSource.cs

@@ -177,6 +177,11 @@ private async Task EvaluateAndShowTooltipAsync (IAsyncQuickInfoSession session,
 			var bounds = view.TextViewLines.GetCharacterBounds (point);
 			var rect = new CoreGraphics.CGRect (bounds.Left - view.ViewportLeft, bounds.Top - view.ViewportTop, bounds.Width, bounds.Height);
 
+			if (cocoaView.IsClosed) {
+				LoggingService.LogWarning ("Editor window has been closed before debugger tooltip was shown. How did this happen?");
+				return;
+			}
+
 			window.Show (rect, cocoaView.VisualElement, AppKit.NSRectEdge.MaxXEdge);
 #else
 			throw new NotImplementedException ();