Mypal 27.9.4 the themed Mypal button reproducibly stops to work after specific steps of maximize/minimize/restore

0.4.11-RC-36-gc5204e3 gcc dbg linux

This is reproducible for me, but the exact order of commands is crucial

Reproduction steps
-download MyPal 27.9.4 from rapps and install its main app
-maximize the application via titlebar
-right click next to the menubar and deselect the menubar (ignore CORE-15303)
-the menubar will vanish and we enter "themed mode" (ignore CORE-8808)
-click the top-left "Mypal"-button (that is only visible in themed mode).
it does open properly a menu at this point
-minimize via the invisible, but working "minimize" button in titlebar (ignore CORE-8808)
-restore the application by single-left-clicking its taskbar pane
now the "MyPal"-button in the top left does not longer open any menu
(in case you would change from maximized state into windowed mode again now by pressing the restore button from titlebar, the "Mypal"-button would start to work again)
0.4.11-RC-36-gc5204e3__Mypal27_9_4.webm
0.4.11-RC-36-gc5204e3__Mypal27_9_4.log
usually the only interesting loggings are these from win32ss/user/ntuser/winpos.c:*
like

(win32ss/user/ntuser/winpos.c:787) err: FIXME: Parent is Desktop, Min off screen!

Expected result
xpsp3_ok.webm
The themed "Mypal"-button should open up, no matter what I did before regarding minimize/maximize/restore

Sidenote
After I did that a few times, I even got continueable Win32SS asserts, but not sure, whether those are related, and I could also not find a way to reproduce those reliably, so they are not needed to be fixed, to allow resolving this ticket.