Change parent of fit deletion dialog

Try out tip mentioned in https://github.com/wxWidgets/Phoenix/issues/1343

gui/builtinShipBrowser/fitItem.py

@@ -344,13 +344,12 @@ class FitItem(SFItem.SFBrowserItem):
         if mstate.GetModifiers() == wx.MOD_SHIFT or mstate.MiddleIsDown():
             self.deleteFit()
         else:
-            dlg = wx.MessageDialog(
-                self, "Do you really want to delete this fit?", "Confirm Delete",
-                wx.YES | wx.NO | wx.ICON_QUESTION)
-            if dlg.ShowModal() == wx.ID_YES:
-                self.deleteFit()
-            else:
-                dlg.Destroy()
+            with wx.MessageDialog(
+                self.GetTopLevelParent(), "Do you really want to delete this fit?", "Confirm Delete",
+                wx.YES | wx.NO | wx.ICON_QUESTION
+            ) as dlg:
+                if dlg.ShowModal() == wx.ID_YES:
+                    self.deleteFit()
 
     def deleteFit(self, event=None):
         pyfalog.debug("Deleting ship fit.")