Fix potential reference after dispose.
Fix potential reference after dispose.

SuperJMN/Avalonia,wieslawsoltes/Perspex,AvaloniaUI/Avalonia,MrDaedra/Avalonia,susloparovdenis/Perspex,wieslawsoltes/Perspex,jkoritzinsky/Perspex,SuperJMN/Avalonia,jkoritzinsky/Avalonia,jkoritzinsky/Avalonia,DavidKarlas/Perspex,susloparovdenis/Avalonia,SuperJMN/Avalonia,grokys/Perspex,wieslawsoltes/Perspex,punker76/Perspex,OronDF343/Avalonia,Perspex/Perspex,sagamors/Perspex,AvaloniaUI/Avalonia,jkoritzinsky/Avalonia,jkoritzinsky/Avalonia,jkoritzinsky/Avalonia,SuperJMN/Avalonia,jkoritzinsky/Avalonia,AvaloniaUI/Avalonia,susloparovdenis/Avalonia,danwalmsley/Perspex,tshcherban/Perspex,Perspex/Perspex,jazzay/Perspex,wieslawsoltes/Perspex,AvaloniaUI/Avalonia,akrisiun/Perspex,AvaloniaUI/Avalonia,OronDF343/Avalonia,AvaloniaUI/Avalonia,MrDaedra/Avalonia,SuperJMN/Avalonia,wieslawsoltes/Perspex,wieslawsoltes/Perspex,SuperJMN/Avalonia,bbqchickenrobot/Perspex,susloparovdenis/Perspex,AvaloniaUI/Avalonia,SuperJMN/Avalonia,ncarrillo/Perspex,wieslawsoltes/Perspex,jkoritzinsky/Avalonia,kekekeks/Perspex,grokys/Perspex,kekekeks/Perspex