Fix "Solution was modified externally" message when SharpDevelop itself modifies the solution.

This was caused because the ProjectChangeWatcher didn't dispose the FileSystemChangeWatcher, so we got reload notifications for unloaded projects when the project was re-loaded and modified.

src/Main/Base/Project/Src/Project/ProjectChangeWatcher.cs

@@ -1,6 +1,7 @@
 // Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
 // This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
 using System;
+using System.Collections.Generic;
 using System.IO;
 using ICSharpCode.Core;
 using ICSharpCode.SharpDevelop.Gui;
@@ -9,6 +10,14 @@ namespace ICSharpCode.SharpDevelop.Project
 {
 	public sealed class ProjectChangeWatcher : IProjectChangeWatcher
 	{
+		static readonly HashSet<ProjectChangeWatcher> activeWatchers = new HashSet<ProjectChangeWatcher>();
+		
+		internal static void OnAllChangeWatchersDisabledChanged()
+		{
+			foreach (ProjectChangeWatcher watcher in activeWatchers)
+				watcher.SetWatcher();
+		}
+		
 		FileSystemWatcher watcher;
 		string fileName;
 		bool enabled = true;
@@ -16,9 +25,13 @@ namespace ICSharpCode.SharpDevelop.Project
 		public ProjectChangeWatcher(string fileName)
 		{
 			this.fileName = fileName;
+			
+			WorkbenchSingleton.AssertMainThread();
+			activeWatchers.Add(this);
+			
 			WorkbenchSingleton.MainWindow.Activated += MainFormActivated;
 		}
-
+		
 		public void Enable()
 		{
 			enabled = true;
@@ -44,7 +57,7 @@ namespace ICSharpCode.SharpDevelop.Project
 				watcher.EnableRaisingEvents = false;
 			}
 
-			if (!enabled)
+			if (!enabled || FileChangeWatcher.AllChangeWatchersDisabled)
 				return;
 
 			if (string.IsNullOrEmpty(fileName))
@@ -90,7 +103,7 @@ namespace ICSharpCode.SharpDevelop.Project
 
 		void OnFileChangedEvent(object sender, FileSystemEventArgs e)
 		{
-			LoggingService.Debug("Solution was changed externally: " + e.ChangeType);
+			LoggingService.Debug("Project file " + e.Name + " was changed externally: {1}" + e.ChangeType);
 			if (!wasChangedExternally) {
 				wasChangedExternally = true;
 				if (WorkbenchSingleton.Workbench.IsActiveWindow) {
@@ -117,8 +130,14 @@ namespace ICSharpCode.SharpDevelop.Project
 
 		public void Dispose()
 		{
+			WorkbenchSingleton.AssertMainThread();
 			if (!disposed) {
 				WorkbenchSingleton.MainWindow.Activated -= MainFormActivated;
+				activeWatchers.Remove(this);
+			}
+			if (watcher != null) {
+				watcher.Dispose();
+				watcher = null;
 			}
 			disposed = true;
 		}

src/Main/Base/Project/Src/Services/File/FileChangeWatcher.cs

@@ -44,12 +44,17 @@ namespace ICSharpCode.SharpDevelop
 		
 		static int globalDisableCount;
 		
+		public static bool AllChangeWatchersDisabled {
+			get { return globalDisableCount > 0; }
+		}
+		
 		public static void DisableAllChangeWatchers()
 		{
 			WorkbenchSingleton.AssertMainThread();
 			globalDisableCount++;
 			foreach (FileChangeWatcher w in activeWatchers)
 				w.SetWatcher();
+			Project.ProjectChangeWatcher.OnAllChangeWatchersDisabledChanged();
 		}
 		
 		public static void EnableAllChangeWatchers()
@@ -60,6 +65,7 @@ namespace ICSharpCode.SharpDevelop
 			globalDisableCount--;
 			foreach (FileChangeWatcher w in activeWatchers)
 				w.SetWatcher();
+			Project.ProjectChangeWatcher.OnAllChangeWatchersDisabledChanged();
 		}
 		
 		public event EventHandler FileChanged;