ux: focus input-less popups so Space in Discard dialog no longer stages the file behind it

Author: corebonts

src/Views/PopupDataTemplates.cs

@@ -1,4 +1,6 @@
-using Avalonia.Controls;
+using System.Linq;
+
+using Avalonia.Controls;
 using Avalonia.Controls.Templates;
 using Avalonia.Input;
 using Avalonia.VisualTree;
@@ -35,6 +37,22 @@ public Control Build(object param)
                         return;
                     }
                 }
+
+                var host = ctl.GetVisualAncestors().OfType<Control>().FirstOrDefault(c => c.Name == "PopupPanel");
+                if (host == null)
+                    return;
+
+                foreach (var input in host.GetVisualDescendants())
+                {
+                    if (input is SelectableTextBlock)
+                        continue;
+
+                    if (input is Control { Focusable: true, IsVisible: true, IsEffectivelyVisible: true, IsEffectivelyEnabled: true } focusable)
+                    {
+                        focusable.Focus(NavigationMethod.Directional);
+                        return;
+                    }
+                }
             };
 
             return control;