Make cursor selection in the app menu more intuitive

[coyotebush]

How to file a helpful issue

The problem you're addressing (if any)

In the new app menu, it's easy to accidentally operate on the wrong qube.

For example, when I want to shut down a qube early in the list, my diagonal cursor path from the qube name to the "Shutdown qube" option often hovers over and selects a different qube name, and I end up shutting down that qube instead. To avoid this, I have to move the cursor either to the right first or very fast.

When the Window Manager option "Automatically give focus to newly created windows" is disabled (to mitigate focus stealing; see also #8728), selecting the first qube requires a click (to focus the menu), so it's particularly surprising to have the selected qube change without another click.

By contrast, the Qubes Domains and Qubes Devices menus are not as sensitive to cursor path (and immediately receive focus).

The solution you'd like

Some ideas:

1. Change qubes only on click instead of hover, as suggested in Qubes App Menu: Provide option to require that (sub)menus be clicked, not hovered #9537
2. Don't change qubes while the cursor is moving towards the sub-menu
3. Make the list of qubes narrower, which probably requires relocating the Apps/Templates/Service tabs

The value to a user, and who that user might be

Users who navigate the app menu by mouse, particularly with "Automatically give focus to newly created windows" disabled, will save time re-navigating the menu and potentially also reversing the effect of a mis-applied action.

Completion criteria checklist

(This section is for developer use only. Please do not modify it.)