rcaelers/workrave — comment on commit 4c4b099beb44cc697b6014610bb27b25d12ff48a
File:  line 0
By rcaelers:

I also noticed this behavior. You have to enter the main menu first for the menu to disappear. It's not perfect, but better than an unusable sub menu that disappears with 500ms. I tried monitoring the submenu; without success...

When leaving a menu or submenu, gtk often (but not always) send a GDK_ENTER_NOTIFY with detail GDK_NOTIFY_INFERIOR. Perhaps that can be used to remove the menu. Needs further investigation...I'm using 2.24.0.