Open LO 7.2.3.2 under Linux with SAL_USE_VCLPLUGIN=gen ./soffice. Try Alt + F → menu 'File' will be opened. Try Ctrl + Alt + F → menu 'File' will be opened also. This behavior appears for 'Help' and many menus when opening an empty writer document (View, Insert, Format …). Same behavior when LO 7.2.3.2 is opened with vcl:gtk3. With vcl:kf5 the combination of Ctrl + Alt + F won't open the menu 'File' and all the other menus. This is the expected behavior. All tested on the same machine, OpenSUSE 15.2 64bit rpm Linux. Bug appears also in LO 7.2.0.4. Could be it is the default behavior of vcl:gen, because it also appears for vcl.gen with LO 7.0.0.
*** This bug has been marked as a duplicate of bug 147062 ***