KMail filters: some filters do not activate shortcut

Hi,


I have some manual filters in KMail. I have assigned all of them shortcuts 
to easily invoke them when one or more messages is selected. For some 
filters, the shortcut is not activated in the sense that it doesn't work 
when pressed and also that it is not listed in the context menu next to the 
filter name. This is independent of the actual shortcut.

Has anyone encountered this as well?


Thanks,

Erik