Fixing FluentTheme Expanded header foreground issue
Fixing FluentTheme Expanded header foreground issue

My first attempt at contributing!

This commit adds a style selector to ensure that the Expanded control keeps its foreground when expanded. Fixes #5349

Tested with 0.10.0 with both Light and Dark themes.

AvaloniaUI/Avalonia,jkoritzinsky/Perspex,jkoritzinsky/Avalonia,AvaloniaUI/Avalonia,jkoritzinsky/Avalonia,SuperJMN/Avalonia,SuperJMN/Avalonia,jkoritzinsky/Avalonia,jkoritzinsky/Avalonia,wieslawsoltes/Perspex,wieslawsoltes/Perspex,SuperJMN/Avalonia,wieslawsoltes/Perspex,Perspex/Perspex,SuperJMN/Avalonia,wieslawsoltes/Perspex,wieslawsoltes/Perspex,AvaloniaUI/Avalonia,SuperJMN/Avalonia,Perspex/Perspex,jkoritzinsky/Avalonia,grokys/Perspex,wieslawsoltes/Perspex,wieslawsoltes/Perspex,SuperJMN/Avalonia,AvaloniaUI/Avalonia,AvaloniaUI/Avalonia,grokys/Perspex,jkoritzinsky/Avalonia,AvaloniaUI/Avalonia,jkoritzinsky/Avalonia,AvaloniaUI/Avalonia,SuperJMN/Avalonia