From 0e98301dc1f2ecd0c533d9c8dd691aedc7c093e4 Mon Sep 17 00:00:00 2001
From: Dmitry Vodich <amid@scand.com>
Date: Fri, 25 Oct 2019 13:21:50 +0300
Subject: [PATCH] Fixed issue #83 with LayoutDocument disappearance.

---
 .../Layout/LayoutContent.cs                   | 24 ++++++++++++++-----
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/source/Components/Xceed.Wpf.AvalonDock/Layout/LayoutContent.cs b/source/Components/Xceed.Wpf.AvalonDock/Layout/LayoutContent.cs
index 848fca18..a7fa47af 100644
--- a/source/Components/Xceed.Wpf.AvalonDock/Layout/LayoutContent.cs
+++ b/source/Components/Xceed.Wpf.AvalonDock/Layout/LayoutContent.cs
@@ -93,11 +93,7 @@ public object Content
 
           if( this.ContentId == null )
           {
-            var contentAsControl = _content as FrameworkElement;
-            if( contentAsControl != null && !string.IsNullOrWhiteSpace( contentAsControl.Name ) )
-            {
-              this.SetCurrentValue( LayoutContent.ContentIdProperty, contentAsControl.Name );
-            }
+            SetContentIdFromContent();
           }
         }
       }
@@ -112,7 +108,13 @@ public string ContentId
     {
       get
       {
-        return (string)GetValue( ContentIdProperty );
+        string value = (string)GetValue(ContentIdProperty);
+        if (!string.IsNullOrWhiteSpace(value)) return value;
+
+        // #83 - if Content.Name is empty at setting content and will be set later, ContentId will stay null.
+        SetContentIdFromContent();
+
+        return (string)GetValue(ContentIdProperty);
       }
       set
       {
@@ -136,6 +138,16 @@ private void OnContentIdPropertyChanged( string oldValue, string newValue )
         this.RaisePropertyChanged( "ContentId" );
       }
     }
+
+    private void SetContentIdFromContent()
+    {
+      var contentAsControl = _content as FrameworkElement;
+      if (!string.IsNullOrWhiteSpace(contentAsControl?.Name))
+      {
+        this.SetCurrentValue(LayoutContent.ContentIdProperty, contentAsControl.Name);
+      }
+    }
+
     #endregion ContentId
 
     #region IsSelected