fix #3550: dialog don't show up the second time
fix #3550: dialog don't show up the second time

KublaikhanGeek/cgeo,rsudev/c-geo-opensource,superspindel/cgeo,brok85/cgeo,pstorch/cgeo,pstorch/cgeo,madankb/cgeo,rsudev/c-geo-opensource,tobiasge/cgeo,kumy/cgeo,mucek4/cgeo,cgeo/cgeo,ThibaultR/cgeo,vishwakulkarni/cgeo,matej116/cgeo,mucek4/cgeo,rsudev/c-geo-opensource,brok85/cgeo,lewurm/cgeo,vishwakulkarni/cgeo,Huertix/cgeo,ThibaultR/cgeo,yummy222/cgeo,KublaikhanGeek/cgeo,madankb/cgeo,Bananeweizen/cgeo,superspindel/cgeo,marco-dev/c-geo-opensource,schwabe/cgeo,matej116/cgeo,samueltardieu/cgeo,yummy222/cgeo,KublaikhanGeek/cgeo,auricgoldfinger/cgeo,Bananeweizen/cgeo,cgeo/cgeo,SammysHP/cgeo,S-Bartfast/cgeo,ThibaultR/cgeo,xiaoyanit/cgeo,madankb/cgeo,brok85/cgeo,samueltardieu/cgeo,SammysHP/cgeo,S-Bartfast/cgeo,kumy/cgeo,cgeo/cgeo,S-Bartfast/cgeo,schwabe/cgeo,xiaoyanit/cgeo,cgeo/cgeo,mucek4/cgeo,vishwakulkarni/cgeo,lewurm/cgeo,auricgoldfinger/cgeo,Bananeweizen/cgeo,yummy222/cgeo,xiaoyanit/cgeo,marco-dev/c-geo-opensource,auricgoldfinger/cgeo,schwabe/cgeo,schwabe/cgeo,tobiasge/cgeo,pstorch/cgeo,superspindel/cgeo,tobiasge/cgeo,samueltardieu/cgeo,Huertix/cgeo,SammysHP/cgeo,matej116/cgeo,lewurm/cgeo,kumy/cgeo,Huertix/cgeo,marco-dev/c-geo-opensource