Applied patch by John Simons: Closing an open file tab returns focus to the previously focused tab. Patch edited slightly to use generics & follow DockPane.cs naming conventions.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@1078 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/Libraries/DockPanel_Src/WinFormsUI/Docking/DockPane.cs

@@ -9,6 +9,7 @@
 // *****************************************************************************
 
 using System;
+using System.Collections.Generic;
 using System.ComponentModel;
 using System.Drawing;
 using System.Drawing.Drawing2D;
@@ -174,6 +175,7 @@ namespace WeifenLuo.WinFormsUI
 			base.Dispose(disposing);
 		}
 
+		private Stack<DockContent> m_visitedTabs = new Stack<DockContent>();
 		private DockContent m_activeContent = null;
 		/// <include file='CodeDoc\DockPane.xml' path='//CodeDoc/Class[@name="DockPane"]/Property[@name="ActiveContent"]/*'/>
 		public virtual DockContent ActiveContent
@@ -202,6 +204,14 @@ namespace WeifenLuo.WinFormsUI
 
 				m_activeContent = value;
 				
+				if (m_activeContent != null && m_activeContent.DockState == DockState.Document)
+				{
+					if (!(m_visitedTabs.Count > 0 && m_visitedTabs.Peek() == m_activeContent))
+					{
+						m_visitedTabs.Push(m_activeContent);
+					}
+				}
+				
 				if (FloatWindow != null)
 					FloatWindow.SetText();
 
@@ -810,6 +820,24 @@ namespace WeifenLuo.WinFormsUI
 				return;
 
 			DockContent prevVisible = null;
+			
+			if (ActiveContent.DockState == DockState.Unknown)
+			{
+				while(m_visitedTabs.Count > 0)
+				{
+					prevVisible = m_visitedTabs.Pop();
+					
+					if (prevVisible != null && !prevVisible.IsDisposed && prevVisible != ActiveContent)
+						break;
+				}
+			}
+			
+			if (prevVisible != null)
+			{
+				ActiveContent = prevVisible;
+			}
+			else
+			{
 				for (int i=Contents.IndexOf(ActiveContent)-1; i>=0; i--)
 					if (Contents[i].DockState == DockState)
 					{
@@ -832,6 +860,7 @@ namespace WeifenLuo.WinFormsUI
 	 			else
 	 				ActiveContent = null;
 			}
+		}
 
 		private static readonly object DockStateChangedEvent = new object();
 		/// <include file='CodeDoc\DockPane.xml' path='//CodeDoc/Class[@name="DockPane"]/Event[@name="DockStateChanged"]/*'/>