Normally, Alt+F1 would open the application launcher (kickoff). But it does not. When I used the widget settings to manually define the keyboard shortcut, there is nothing preset. When I try to assign... - Alt+F1, it will not be accepted and there is no message why. - Alt+F2, krunner is shown - Alt+F6, it works
alt f1 works here. There must be something else stealing your alt+f1
I found the problem. In the Shortcuts settings dialog for KDE component "Plasma" there are Actions: (1) "Activate Anwendungs-Starter Widget" (2) "Activate Anwendungsmenü Widget" The Alt+F1 was set to (2). I use the menu which was default in KDE4 and therefore the setting was grabbing away the key but had no effect. Now, I set Alt+F1 to (1) which solved the problem. Still, I for the normal user it is not easily possible to know to what the options (1) and (2) are referring to.