Peculiar behavior trying to set active menu item

[John Sturtz]

------ Original Message ------
>From "Charles" <peacech at gmail.com>
To "John Sturtz" <john at sturtz.org>
Cc pyqt at riverbankcomputing.com
Date 3/5/2025 7:15:55 PM
Subject Re: Peculiar behavior trying to set active menu item

>If you look at 
>https://codebrowser.dev/qt6/qtbase/src/widgets/widgets/qmenu.cpp.html#_ZN5QMenu10timerEventEP11QTimerEvent, 
>QMenu has a timerEvent. This resets the highlight.
>
>What you can do is store the active item in an attribute and reselect 
>it after the timerEvent
>
>def timerEvent(self, event):
>         super().timerEvent(event)
>         if self._active_action:
>             self.setActiveAction(self._active_action)
>
Without having looked at the source, I was already coming to that 
conclusion.  The time duration before the highlight disappeared was so 
consistent, it felt like it must be controlled by a timer.

So I installed an event filter on the menu, and sure enough, shortly 
after typing 'A' to select the first menu item, the menu receives a 
Timer event, followed by an UpdateRequest event.

It isn't obvious to me why it does this.  Indeed, if I just suppress it:

     def timerEvent(self, event):
         return

it seems to work fine.  But I expect someone must have thought there was 
a good reason for it at some point, and I imagine if I took this 
approach, it would probably eventually bite me somehow.

Another possible approach is to query the active action from 
timerEvent() and save it, prior to calling super() (which I presumes is 
responsible for the reset), then use that to reselect it afterward:

     def timerEvent(self, event):
         active_action = self.activeAction()
         super().timerEvent(timer)
         self.setActiveAction(active_action)

This seems to work also.

Thank you again for your help!

/John
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