Fix for SD-1150

src/Main/Base/Project/Src/Commands/FileMenuCommands.cs

@@ -40,8 +40,7 @@ public class CloseSolution : AbstractMenuCommand
 		public override void Run()
 		{
 			ProjectService.SaveSolutionPreferences();
-			WorkbenchSingleton.Workbench.CloseAllViews();
-			if (WorkbenchSingleton.Workbench.WorkbenchWindowCollection.Count == 0) {
+			if (WorkbenchSingleton.Workbench.CloseAllSolutionViews()) {
 				ProjectService.CloseSolution();
 			}
 		}

src/Main/Base/Project/Src/Gui/IWorkbench.cs

@@ -163,6 +163,14 @@ bool IsActiveWindow {
 		/// </summary>
 		void CloseAllViews();
 
+		/// <summary>
+		/// 	Closes all views related to current solution.
+		/// </summary>
+		/// <returns>
+		/// 	True if all views were closed properly, false if closing was aborted.
+		/// </returns>
+		bool CloseAllSolutionViews();
+
 		/// <summary>
 		/// Is called, when a workbench view was opened
 		/// </summary>

src/Main/Base/Project/Src/Gui/Workbench/WpfWorkbench.cs

@@ -17,6 +17,7 @@
 using System.Windows.Navigation;
 using ICSharpCode.Core;
 using ICSharpCode.Core.Presentation;
+using ICSharpCode.SharpDevelop.Project;
 
 namespace ICSharpCode.SharpDevelop.Gui
 {
@@ -433,6 +434,46 @@ public void CloseAllViews()
 			}
 		}
 
+		public bool CloseAllSolutionViews()
+		{
+			bool isSolutionWindow;
+			bool result = true;
+
+			WorkbenchSingleton.AssertMainThread();
+			try
+			{
+				closeAll = true;
+				foreach (IWorkbenchWindow window in this.WorkbenchWindowCollection.ToArray())
+				{
+					isSolutionWindow = false;
+					foreach (IViewContent content in window.ViewContents)
+					{
+						foreach (OpenedFile file in content.Files)
+						{
+							if (ProjectService.OpenSolution.FindProjectContainingFile(file.FileName) != null)
+							{
+								isSolutionWindow = true;
+								break;							
+							}
+						}
+
+						if (isSolutionWindow)
+							break;
+					}
+
+					if (isSolutionWindow)
+						result = window.CloseWindow(false) && result;
+				}
+			}
+			finally
+			{
+				closeAll = false;
+				OnActiveWindowChanged(this, EventArgs.Empty);
+			}
+
+			return result;
+		}
+
 		#region ViewContent Memento Handling
 		string viewContentMementosFileName;