Always append ".csproj" extension when saving as project.

ILSpy/TreeNodes/AssemblyTreeNode.cs

@@ -210,7 +210,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			if (string.IsNullOrEmpty(language.ProjectFileExtension))
 				return false;
 			SaveFileDialog dlg = new SaveFileDialog();
-			dlg.FileName = DecompilerTextView.CleanUpName(assembly.ShortName);
+			dlg.FileName = DecompilerTextView.CleanUpName(assembly.ShortName) + language.ProjectFileExtension;
 			dlg.Filter = language.Name + " project|*" + language.ProjectFileExtension + "|" + language.Name + " single file|*" + language.FileExtension + "|All files|*.*";
 			if (dlg.ShowDialog() == true) {
 				DecompilationOptions options = new DecompilationOptions();