You can assign a QAction as "action", this way you can just pass it e.g. plasmoid.action("configure").
However, when assigning a null action as can happen with kiosk restrictions, it would crash
as it assigns m_action the nullptr but never checks for that.
This patch ensures we always have a QAction, creating a new empty one, if neccessary.
Also deletes our own action if an external one is assigned
Differential Revision: https://phabricator.kde.org/D6608
This allows to limit the maximum width of a menu. It can be useful for instance
in task manager where long file names for recent documents will result in gigantic menus.
The property has a RESET method (which is called if you assign "undefined") which will
set it back to QWIDGETSIZE_MAX to remove the size restriction.
Differential Revision: https://phabricator.kde.org/D4257
