Update MathCATPreferences.py

return from OnClickCancel prevent an annoying audible alert

Author: ways2read

NVDA-addon/addon/globalPlugins/MathCAT/MathCATPreferences.py

@@ -193,6 +193,7 @@ def MathCATPreferencesDialogOnCharHook(self,event):
         keyCode = event.GetKeyCode()
         if keyCode == wx.WXK_ESCAPE:
             UserInterface.OnClickCancel(self,event)
+            return
         if keyCode == wx.WXK_RETURN:
             UserInterface.OnClickOK(self,event)
         if keyCode == wx.WXK_TAB and (event.GetModifiers()  == wx.MOD_CONTROL):