Fix SD-1703 - Deleted and removed projects remain in the solution

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

@@ -452,8 +452,6 @@ namespace ICSharpCode.SharpDevelop.Project
 		{
 			ProjectSection nestedProjectsSection = null;
 			
-			bool needsConversion = false;
-			
 			// read solution files using system encoding, but detect UTF8 if BOM is present
 			using (StreamReader sr = new StreamReader(newSolution.FileName, Encoding.Default, true)) {
 				string line = GetFirstNonCommentLine(sr);
@@ -465,17 +463,9 @@ namespace ICSharpCode.SharpDevelop.Project
 				
 				switch (match.Result("${Version}")) {
 					case "7.00":
-						needsConversion = true;
-						if (!MessageService.AskQuestion("${res:SharpDevelop.Solution.ConvertSolutionVersion7}")) {
-							return false;
-						}
-						break;
 					case "8.00":
-						needsConversion = true;
-						if (!MessageService.AskQuestion("${res:SharpDevelop.Solution.ConvertSolutionVersion8}")) {
-							return false;
-						}
-						break;
+						MessageService.ShowError("${res:SharpDevelop.Solution.CannotLoadOldSolution}");
+						return false;
 					case "9.00":
 					case "10.00":
 					case "11.00":
@@ -503,7 +493,7 @@ namespace ICSharpCode.SharpDevelop.Project
 				}
 			}
 			
-			if (!newSolution.ReadOnly && (newSolution.FixSolutionConfiguration(newSolution.Projects) || needsConversion)) {
+			if (!newSolution.ReadOnly && (newSolution.FixSolutionConfiguration(newSolution.Projects))) {
 				// save in new format
 				newSolution.Save();
 			}

src/Main/Base/Project/Src/Services/ProjectService/ProjectService.cs

@@ -624,9 +624,11 @@ namespace ICSharpCode.SharpDevelop.Project
 		
 		static void HandleRemovedSolutionFolder(ISolutionFolder folder)
 		{
-			if (folder is IProject) {
-				OpenSolution.RemoveProjectConfigurations(folder.IdGuid);
-				ParserService.RemoveProjectContentForRemovedProject((IProject)folder);
+			IProject project = folder as IProject;
+			if (project != null) {
+				OpenSolution.RemoveProjectConfigurations(project.IdGuid);
+				ParserService.RemoveProjectContentForRemovedProject(project);
+				project.Dispose();
 			}
 			if (folder is ISolutionFolderContainer) {
 				// recurse into child folders that were also removed