Modify onscreen End Call Button behavior?

[skw]

I've just noticed that when I'm in call and trying to hit the external speaker or notes button, I sometimes accidentally press the big 'End Call' button, but even if I hold it down and slide my finger off of it the call still ends.

This does not happen with the start menu or program/settings menu where a click is only registered when the finger lets go of the screen. Is there any way to change the 'end call' button to this?