We should allow HostMainWindow to be activated to support the pickers.

src/RhinoInside.Revit.External/ActivationGate.cs

@@ -440,16 +440,19 @@ protected override int DispatchHook(int nCode, IntPtr wParam, IntPtr lParam)
             if (IsOpen)
             {
               var window = (WindowHandle) wParam;
-              if (HostMainWindow.Enabled && !IsExternalWindow(window, out var _))
+              if (HostMainWindow != window)
               {
-                foreach (var gate in gates)
+                if (!HostMainWindow.Enabled && !IsExternalWindow(window, out var _))
                 {
-                  try { gate.Value.Window.BringToFront(); }
-                  catch { }
-                }
+                  foreach (var gate in gates)
+                  {
+                    try { gate.Value.Window.BringToFront(); }
+                    catch { }
+                  }
 
-                windowToActivate = window; // Will be activated when our message loop is Idle.
-                return 1; // Prevents activation now.
+                  windowToActivate = window; // Will be activated when our message loop is Idle.
+                  return 1; // Prevents activation now.
+                }
               }
             }
             else

src/RhinoInside.Revit.External/UI/UIHostApplicationUnconstrained.cs

@@ -77,7 +77,7 @@ private async void UpdateOpenViewsList(object sender, ViewActivatedEventArgs e)
     {
       OpenViews.Clear();
 
-      // Calling GetOpenViews here is not safe, so we yeld until Idle to do so.
+      // Calling GetOpenViews here is not safe, so we yield until Idle to do so.
       await ActivationGate.Yield();
       OpenViews = new HashSet<View>(_app.Application.GetOpenViews(), ElementEqualityComparer.InterDocument);
     }

src/RhinoInside.Revit/Rhinoceros.cs

@@ -40,10 +40,6 @@ internal static bool InitEto(Assembly assembly)
       if (Eto.Forms.Application.Instance is null)
         new Eto.Forms.Application(Eto.Platforms.Wpf).Attach();
 
-#if RHINO_8
-      Eto.Wpf.Forms.Controls.TextBoxHandler.EnableNoGCRegionDefault = false;
-#endif
-
       return true;
     }