Purely aesthetics.

 

[attachment=4639:PM window sizing.png]

 

Scroll bar on far right should ideally not exist, a couple of line breaks may need removing, above and below the sorting cloud would likely be most effective, as well as reducing the scroll panel length to the left - though this latter one might interfere with the interface for those without the extra PM features.

You have too many labels, that's why. Such outrageous amount of them wasn't considered when pm popup was designed :p

I believe this is an issue with you choosing to have too many labels. It would be possible to disable the scrollbar, but that would make it difficult for most to be able to scroll down. The other solutions are to make the label link text smaller, or to use a button to expand the labels and have them collapsed by default.

This has been resolved.