QAction visibility change in QMenu::aboutToShow results in poor menu placement

Steps to Reproduce:

• See attached main.cpp
• Run, and place window near the bottom of the screen (see example image)
• Select a menu

Results:

• Resulting popup menu is positioned in a weird/floating/unexpected location

Expected Results:

• Resulting popup menu is placed in nice alignment with the Menu title

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Updating the visibility of QActions in QMenu just before the menu is shown (QMenu::aboutToShow connection) results in poor placement of the menus. See the attached example image.

It appears to draw poorly when the length of the menu - before visibility changes - exceeds available vertical drawing space. This is troublesome when your application has a QMenu with a long, long list of QActions, even though only a small subset are visible at any time.

As noted, at the end of AboutToShow I've tried:

• update, updateGeometry, adjustSize(), ensurePolished with both pMenu and pMenu->parentWidget()
• invalidating the layout, but neither pMenu nor pMenu->parentWidget have a valid widget at this point.

Posting this issue on the Qt Forums, it was recommended to file a bug (any related bugs in this database appear to have already been resolved):
https://forum.qt.io/topic/68765/how-to-update-geometry-on-qaction-visibility-change-in-qmenu-abouttoshow/2