Comment 32 for bug 45843

Bug 123657 informs us that the same thing happens for right-click menus. Bug 107696 notes that it applies when passive windows pop up; "say for example autocomplete/intellisense in KDevelop".

So we have:
1) Combo boxes and friends (e.g. address field in Konqueror, autocomplete/form field suggestions on web pages)
2) Menus: application menus, RMB menus, K menu
3) (anything else?)