Fix potential crash when fBrowser pointer is NULL, as reported on the forum (https://root.cern.ch/phpBB3/viewtopic.php?f=3&t=19438)
Fix potential crash when fBrowser pointer is NULL, as reported on the forum (https://root.cern.ch/phpBB3/viewtopic.php?f=3&t=19438)

perovic/root,zzxuanyuan/root,mhuwiler/rootauto,BerserkerTroll/root,zzxuanyuan/root-compressor-dummy,sawenzel/root,BerserkerTroll/root,bbockelm/root,Duraznos/root,Y--/root,olifre/root,Y--/root,bbockelm/root,mkret2/root,lgiommi/root,georgtroska/root,olifre/root,beniz/root,nilqed/root,simonpf/root,bbockelm/root,evgeny-boger/root,sbinet/cxx-root,mattkretz/root,vukasinmilosevic/root,CristinaCristescu/root,BerserkerTroll/root,CristinaCristescu/root,buuck/root,agarciamontoro/root,bbockelm/root,sirinath/root,zzxuanyuan/root,satyarth934/root,root-mirror/root,nilqed/root,sirinath/root,nilqed/root,beniz/root,dfunke/root,beniz/root,sawenzel/root,georgtroska/root,abhinavmoudgil95/root,thomaskeck/root,davidlt/root,bbockelm/root,simonpf/root,bbockelm/root,beniz/root,lgiommi/root,georgtroska/root,abhinavmoudgil95/root,omazapa/root,veprbl/root,abhinavmoudgil95/root,omazapa/root,omazapa/root,gganis/root,mkret2/root,krafczyk/root,Duraznos/root,nilqed/root,krafczyk/root,evgeny-boger/root,zzxuanyuan/root,zzxuanyuan/root-compressor-dummy,Y--/root,evgeny-boger/root,zzxuanyuan/root,Y--/root,root-mirror/root,pspe/root,esakellari/root,CristinaCristescu/root,dfunke/root,mhuwiler/rootauto,arch1tect0r/root,krafczyk/root,evgeny-boger/root,esakellari/root,dfunke/root,veprbl/root,jrtomps/root,sbinet/cxx-root,simonpf/root,thomaskeck/root,jrtomps/root,evgeny-boger/root,lgiommi/root,gganis/root,olifre/root,perovic/root,mattkretz/root,jrtomps/root,mkret2/root,mattkretz/root,pspe/root,zzxuanyuan/root,root-mirror/root,esakellari/root,jrtomps/root,satyarth934/root,georgtroska/root,evgeny-boger/root,omazapa/root,perovic/root,sawenzel/root,lgiommi/root,pspe/root,krafczyk/root,sirinath/root,olifre/root,olifre/root,satyarth934/root,root-mirror/root,mattkretz/root,zzxuanyuan/root-compressor-dummy,mhuwiler/rootauto,sbinet/cxx-root,mhuwiler/rootauto,simonpf/root,root-mirror/root,BerserkerTroll/root,thomaskeck/root,dfunke/root,esakellari/root,pspe/root,davidlt/root,zzxuanyuan/root,karies/root,lgiommi/root,jrtomps/root,mkret2/root,davidlt/root,dfunke/root,bbockelm/root,beniz/root,zzxuanyuan/root,buuck/root,CristinaCristescu/root,mkret2/root,root-mirror/root,zzxuanyuan/root-compressor-dummy,mattkretz/root,satyarth934/root,georgtroska/root,sbinet/cxx-root,CristinaCristescu/root,thomaskeck/root,davidlt/root,root-mirror/root,evgeny-boger/root,evgeny-boger/root,Duraznos/root,lgiommi/root,buuck/root,root-mirror/root,krafczyk/root,sawenzel/root,georgtroska/root,davidlt/root,agarciamontoro/root,mkret2/root,esakellari/root,sawenzel/root,olifre/root,esakellari/root,agarciamontoro/root,evgeny-boger/root,simonpf/root,Duraznos/root,dfunke/root,zzxuanyuan/root-compressor-dummy,gbitzes/root,olifre/root,thomaskeck/root,vukasinmilosevic/root,vukasinmilosevic/root,sawenzel/root,zzxuanyuan/root-compressor-dummy,CristinaCristescu/root,pspe/root,gbitzes/root,krafczyk/root,satyarth934/root,BerserkerTroll/root,veprbl/root,davidlt/root,arch1tect0r/root,olifre/root,veprbl/root,arch1tect0r/root,agarciamontoro/root,perovic/root,krafczyk/root,agarciamontoro/root,nilqed/root,omazapa/root,sbinet/cxx-root,buuck/root,krafczyk/root,veprbl/root,omazapa/root,Y--/root,sawenzel/root,agarciamontoro/root,arch1tect0r/root,sirinath/root,buuck/root,arch1tect0r/root,arch1tect0r/root,simonpf/root,mhuwiler/rootauto,abhinavmoudgil95/root,Duraznos/root,veprbl/root,sbinet/cxx-root,lgiommi/root,nilqed/root,BerserkerTroll/root,esakellari/root,vukasinmilosevic/root,dfunke/root,davidlt/root,gbitzes/root,gganis/root,sawenzel/root,evgeny-boger/root,bbockelm/root,gbitzes/root,BerserkerTroll/root,gganis/root,karies/root,krafczyk/root,esakellari/root,thomaskeck/root,sirinath/root,root-mirror/root,nilqed/root,simonpf/root,abhinavmoudgil95/root,buuck/root,nilqed/root,Duraznos/root,zzxuanyuan/root-compressor-dummy,sbinet/cxx-root,olifre/root,mhuwiler/rootauto,beniz/root,gbitzes/root,krafczyk/root,zzxuanyuan/root-compressor-dummy,BerserkerTroll/root,vukasinmilosevic/root,pspe/root,buuck/root,mkret2/root,zzxuanyuan/root-compressor-dummy,nilqed/root,karies/root,sbinet/cxx-root,mattkretz/root,simonpf/root,zzxuanyuan/root,arch1tect0r/root,gganis/root,BerserkerTroll/root,agarciamontoro/root,gbitzes/root,sirinath/root,zzxuanyuan/root-compressor-dummy,mkret2/root,Duraznos/root,CristinaCristescu/root,mhuwiler/rootauto,nilqed/root,omazapa/root,vukasinmilosevic/root,zzxuanyuan/root,Y--/root,beniz/root,veprbl/root,evgeny-boger/root,sirinath/root,zzxuanyuan/root-compressor-dummy,dfunke/root,gganis/root,zzxuanyuan/root,CristinaCristescu/root,mattkretz/root,gganis/root,lgiommi/root,karies/root,olifre/root,mkret2/root,Y--/root,zzxuanyuan/root,mhuwiler/rootauto,BerserkerTroll/root,olifre/root,karies/root,dfunke/root,georgtroska/root,buuck/root,georgtroska/root,gganis/root,mattkretz/root,jrtomps/root,esakellari/root,gbitzes/root,satyarth934/root,dfunke/root,davidlt/root,thomaskeck/root,mkret2/root,buuck/root,omazapa/root,root-mirror/root,mattkretz/root,CristinaCristescu/root,georgtroska/root,jrtomps/root,Duraznos/root,gbitzes/root,karies/root,sirinath/root,simonpf/root,Y--/root,gganis/root,vukasinmilosevic/root,perovic/root,perovic/root,veprbl/root,georgtroska/root,beniz/root,abhinavmoudgil95/root,arch1tect0r/root,veprbl/root,BerserkerTroll/root,mhuwiler/rootauto,lgiommi/root,CristinaCristescu/root,mkret2/root,omazapa/root,gganis/root,gbitzes/root,Duraznos/root,vukasinmilosevic/root,veprbl/root,abhinavmoudgil95/root,satyarth934/root,agarciamontoro/root,pspe/root,nilqed/root,perovic/root,davidlt/root,bbockelm/root,pspe/root,thomaskeck/root,CristinaCristescu/root,zzxuanyuan/root,thomaskeck/root,lgiommi/root,sbinet/cxx-root,satyarth934/root,arch1tect0r/root,esakellari/root,pspe/root,gganis/root,esakellari/root,satyarth934/root,Y--/root,Y--/root,omazapa/root,mattkretz/root,mattkretz/root,perovic/root,agarciamontoro/root,abhinavmoudgil95/root,vukasinmilosevic/root,Y--/root,agarciamontoro/root,perovic/root,root-mirror/root,arch1tect0r/root,jrtomps/root,sirinath/root,simonpf/root,buuck/root,agarciamontoro/root,satyarth934/root,pspe/root,karies/root,buuck/root,krafczyk/root,perovic/root,jrtomps/root,georgtroska/root,karies/root,vukasinmilosevic/root,perovic/root,sirinath/root,mhuwiler/rootauto,sirinath/root,sbinet/cxx-root,satyarth934/root,simonpf/root,sbinet/cxx-root,dfunke/root,thomaskeck/root,mhuwiler/rootauto,veprbl/root,bbockelm/root,Duraznos/root,vukasinmilosevic/root,arch1tect0r/root,omazapa/root,abhinavmoudgil95/root,gbitzes/root,lgiommi/root,Duraznos/root,karies/root,beniz/root,davidlt/root,gbitzes/root,abhinavmoudgil95/root,sawenzel/root,bbockelm/root,jrtomps/root,davidlt/root,sawenzel/root,karies/root,abhinavmoudgil95/root,jrtomps/root,karies/root,beniz/root,sawenzel/root,pspe/root,beniz/root