Backport fix NullReferenceException in X11Window.Activate#14787

maxkatz6 merged 1 commit intoAvaloniaUI:release/11.0AvaloniaUI/Avalonia:release/11.0from

pos777:backport_fix_x11window_activatepos777/Avalonia:backport_fix_x11window_activateCopy head branch name to clipboard