Spark 2.5.5: Broadcast window resizing issue

If you try to resize broadcast window (Actions > Broadcast message) to be able to see more contacts, it messes up. Seems that Spark is trying to display all contacts without scrollbar and window gets out of bounds.

also, if you expand it horizontally, you can’'t reduce it

update:

this happens in windows, however linux (ubunto 7.04) resizing works fine.

also this window doesnt save its position and size after closing it (Windows)