#14 group headers

[michaeljpastor]

One thing that has always bugged me about pidgin is the buddy list group headers: if I want to rearrange my groups, and I click on a group name header, it either collapses or expands. It would be nice if opening or closing a group was limited to clicking on the +/- symbol so that I could grab a group without having the UI jump all over the place on me.

This may be a separate submission, but "collapse all" and "expand all" would be nice somewhere near the top or bottom.