KF5 tab style issues

[Michal Humpula]

Hi there,

I've encountered strange issue with the style of kf5 kdevelop tabs. 
Specifically the close button takes more space then anything else. It seems to 
be drawn by QCommonStyle class, which is inherited by KStyle.

What I'm not sure, where is the bug. Is it in the
* QCommonStyle because it draws that big close button, or
* KStyle because it does not override close button by itself, or
* my specific style/setup combo, which I'm not sure what it is because Qt5 
seems to choosing proper style magically by itself?

As for the last one, I've seen it on at least one other machine (scummos), so 
it doesn't seems to be specific to my setup.

Any hint, what should I fix, would be appreciated

Cheers
Michal