From 50f595106037fb32e7c44a682b61e135cbd6a13d Mon Sep 17 00:00:00 2001
From: Dmitry Vodich <amid@scand.com>
Date: Thu, 5 Dec 2019 16:04:17 +0300
Subject: [PATCH] Resolve #98 with floating window without a content shown as
 black rectangle

---
 .../LayoutAnchorableFloatingWindowControl.cs  | 11 +++++++++
 .../Xceed.Wpf.AvalonDock/DockingManager.cs    | 23 ++++++++++++++++---
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/source/Components/Xceed.Wpf.AvalonDock/Controls/LayoutAnchorableFloatingWindowControl.cs b/source/Components/Xceed.Wpf.AvalonDock/Controls/LayoutAnchorableFloatingWindowControl.cs
index 38bc2829..7d1809a1 100644
--- a/source/Components/Xceed.Wpf.AvalonDock/Controls/LayoutAnchorableFloatingWindowControl.cs
+++ b/source/Components/Xceed.Wpf.AvalonDock/Controls/LayoutAnchorableFloatingWindowControl.cs
@@ -61,6 +61,8 @@ internal LayoutAnchorableFloatingWindowControl(LayoutAnchorableFloatingWindow mo
 			{
 				root.Updated += OnRootUpdated;
 			}
+
+			_model.IsVisibleChanged += _model_IsVisibleChanged;
 		}
 
 		private void OnRootUpdated(object sender, EventArgs e)
@@ -194,6 +196,7 @@ protected override void OnClosed(EventArgs e)
 			BindingOperations.ClearBinding(_model, VisibilityProperty);
 
 			_model.PropertyChanged -= new System.ComponentModel.PropertyChangedEventHandler(_model_PropertyChanged);
+			_model.IsVisibleChanged -= _model_IsVisibleChanged;
 			Activated -= LayoutAnchorableFloatingWindowControl_Activated;
 			IsVisibleChanged -= this.LayoutAnchorableFloatingWindowControl_IsVisibleChanged;
 			BindingOperations.ClearBinding(this, VisibilityProperty);
@@ -285,6 +288,14 @@ private void _model_PropertyChanged(object sender, System.ComponentModel.Propert
 			}
 		}
 
+		private void _model_IsVisibleChanged(object sender, EventArgs e)
+		{
+			if (!this.IsVisible && _model.IsVisible)
+			{
+				this.Show();
+			}
+		}
+
 		private void CreateOverlayWindow()
 		{
 			if (_overlayWindow == null)
diff --git a/source/Components/Xceed.Wpf.AvalonDock/DockingManager.cs b/source/Components/Xceed.Wpf.AvalonDock/DockingManager.cs
index 3c8b8b50..3fc71bd2 100644
--- a/source/Components/Xceed.Wpf.AvalonDock/DockingManager.cs
+++ b/source/Components/Xceed.Wpf.AvalonDock/DockingManager.cs
@@ -195,7 +195,17 @@ protected virtual void OnLayoutChanged(LayoutRoot oldLayout, LayoutRoot newLayou
 						fw.WindowState = WindowState.Maximized;
 					}
 					else
-						fw.Show();
+					{
+						if (fw.Content != null || (fw.Model as LayoutAnchorableFloatingWindow)?.IsVisible == true)
+						{
+							fw.Show();
+						}
+						else
+						{
+							fw.Hide();
+						}
+					}
+
 					//fw.Owner = Window.GetWindow(this);
 					//fw.SetParentToMainWindowOf(this);
 				}
@@ -2100,8 +2110,15 @@ internal UIElement CreateUIElementForModel(ILayoutElement model)
 
 				Dispatcher.BeginInvoke(new Action(() =>
 			  {
-				  newFW.Show();
-			  }), DispatcherPriority.Send);
+					if (newFW.Content != null || (newFW.Model as LayoutAnchorableFloatingWindow)?.IsVisible == true)
+					{
+						newFW.Show();
+					}
+					else
+					{
+						newFW.Hide();
+					}
+				}), DispatcherPriority.Send);
 
 				if (panegroup != null && panegroup.IsMaximized)
 				{