X11 Error encountered: 
  Error: BadWindow (invalid Window parameter)
  Request:     38 (X_QueryPointer)
  Resource ID: 0x5A
  Serial:      1734
  Hwnd:        Hwnd, Mapped:False ClientWindow:0x5A, WholeWindow:0x5A, Parent:[<null>]
  Control:     <handle 90 non-existant>
         at System.Windows.Forms.XplatUIX11.WhereString () [XplatUIX11.cs:448]
         at System.Windows.Forms.XplatUIX11.HandleError () [XplatUIX11.cs:1461]
         at System.Windows.Forms.XplatUIX11.HandleError ()
         at System.Windows.Forms.XplatUIX11.XQueryPointer ()
         at System.Windows.Forms.XplatUIX11.XQueryPointer ()
         at System.Windows.Forms.XplatUIX11.GetCursorPos () [XplatUIX11.cs:2858]
         at System.Windows.Forms.XplatUI.GetCursorPos () [XplatUI.cs:483]
         at System.Windows.Forms.Cursor.get_Position () [Cursor.cs:214]
         at System.Windows.Forms.Control.get_MousePosition () [Control.cs:1366]
         at System.Windows.Forms.ComboBox.WndProc () [ComboBox.cs:883]
         at System.Windows.Forms.Control+ControlNativeWindow.WndProc () [Control.cs:161]
         at System.Windows.Forms.NativeWindow.WndProc () [NativeWindow.cs:145]
         at System.Windows.Forms.XplatUIX11.DispatchMessage () [XplatUIX11.cs:2669]
         at System.Windows.Forms.XplatUI.DispatchMessage () [XplatUI.cs:419]
         at System.Windows.Forms.Application.RunLoop () [Application.cs:489]
         at System.Windows.Forms.Application.Run () [Application.cs:379]