Having to selected the Entity Twice to complete the action

Hi Guys,
This happens with all features but here's an example:
E.g. Fillet
Fillet command entered, prompt to select first line, select first line and again same prompt to select first line, after selecting it twice it does the same for the second line having to slected it twice again before filleting.
Note it is not related to PICKFIRST command or Mouse at all.

Thanks for your help