Fix Preferences crash when adding new extractor
Fix Preferences crash when adding new extractor

Due to changes for OS X preferences, removing the newly added extractor
on cancel would crash. Fix by disabling data transfer on window
activation when editing the extractors.

alexhenrie/poedit,egoitzro/poedit,dwaynebailey/poedit,BenKeyFSI/poedit,babycaseny/poedit,c72578/poedit,huoxudong125/poedit,egoitzro/poedit,PKRoma/poedit,dwaynebailey/poedit,BenKeyFSI/poedit,c72578/poedit,c72578/poedit,vslavik/poedit,babycaseny/poedit,PatidarWeb/poedit,babycaseny/poedit,alexhenrie/poedit,nawawi/poedit,PKRoma/poedit,PatidarWeb/poedit,huoxudong125/poedit,nawawi/poedit,dwaynebailey/poedit,babycaseny/poedit,PatidarWeb/poedit,PatidarWeb/poedit,nawawi/poedit,PKRoma/poedit,vslavik/poedit,BenKeyFSI/poedit,egoitzro/poedit,alexhenrie/poedit,dwaynebailey/poedit,nawawi/poedit,BenKeyFSI/poedit,egoitzro/poedit,babycaseny/poedit,egoitzro/poedit,alexhenrie/poedit,vslavik/poedit,huoxudong125/poedit,PatidarWeb/poedit,vslavik/poedit,nawawi/poedit,huoxudong125/poedit,c72578/poedit,c72578/poedit,BenKeyFSI/poedit,PKRoma/poedit,PKRoma/poedit,vslavik/poedit,alexhenrie/poedit,dwaynebailey/poedit,huoxudong125/poedit