instead of removing existing selection rects on mousedown - a new one is only added if none exists so far
instead of removing existing selection rects on mousedown - a new one is only added if none exists so far

BioInf-Wuerzburg/AliTV,BioInf-Wuerzburg/AliTV,BioInf-Wuerzburg/AliTV,BioInf-Wuerzburg/AliTV,BioInf-Wuerzburg/AliTV,AliTVTeam/AliTV,AliTVTeam/AliTV,BioInf-Wuerzburg/AliTV