Added mouse-select to TextBox.
Added mouse-select to TextBox.

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