Clear items when Items changes.
Clear items when Items changes.

This allows us to work with lazily-evaluated IEnumerables.

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