make krunner (alt+f2) to NOT search in kmail emails

[O. Sinclair]

Dear Community,

I often use the Alt+F2 to open frequently used documents or start 
applications, sometimes to make snap calculations.

I do however never use it to search for mail in KMail as that is just 
not my workflow. So the x number of mail that comes up as a result is 
nothing but an irritation for me.

Does anyone know how I can limit Krunner to NOT include mail search results?

Kind regards,
Sinclair