Do not change the code completion binding API.

Prevent the CtrlShiftSpace support from breaking existing addins that
use ICodeCompletionBinding by adding another optional interface
IInsightCodeCompletionBinding that includes the new method.

src/AddIns/BackendBindings/AspNet.Mvc/Project/Src/Completion/RazorCSharpCompletionBinding.cs

@@ -48,11 +48,6 @@ namespace ICSharpCode.AspNet.Mvc.Completion
 			return false;
 		}
 
-		public bool CtrlShiftSpace(ITextEditor editor)
-		{
-			return false;
-		}
-
 		public CodeCompletionKeyPressResult HandleKeyPress(ITextEditor editor, char ch)
 		{
 			// We use HandleKeyPressed instead.

src/AddIns/BackendBindings/CSharpBinding/Project/Src/Completion/CSharpCompletionBinding.cs

@@ -35,7 +35,7 @@ using CSharpBinding.FormattingStrategy;
 
 namespace CSharpBinding.Completion
 {
-	public class CSharpCompletionBinding : ICodeCompletionBinding
+	public class CSharpCompletionBinding : ICodeCompletionBinding, IInsightCodeCompletionBinding
 	{
 		ICodeContext context;
 		TextLocation currentLocation;

src/AddIns/BackendBindings/XamlBinding/XamlBinding/XamlCodeCompletionBinding.cs

@@ -244,11 +244,6 @@ namespace ICSharpCode.XamlBinding
 			return false;
 		}
 
-		public bool CtrlShiftSpace(ITextEditor editor)
-		{
-			return false;
-		}
-
 		void DoTriggerCompletion(XamlCompletionContext context, XamlCompletionItemList completionList)
 		{
 			bool isExplicit;

src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/CodeEditor.cs

@@ -631,7 +631,7 @@ namespace ICSharpCode.AvalonEdit.AddIn
 				return;
 
 			CodeEditorView textEditor = GetTextEditorFromSender(sender);
-			foreach (ICodeCompletionBinding cc in CodeCompletionBindings) {
+			foreach (IInsightCodeCompletionBinding cc in CodeCompletionBindings.OfType<IInsightCodeCompletionBinding>()) {
 				if (cc.CtrlShiftSpace(textEditor.Adapter)) {
 					e.Handled = true;
 					break;

src/AddIns/DisplayBindings/XmlEditor/Project/Src/XmlCodeCompletionBinding.cs

@@ -98,11 +98,6 @@ namespace ICSharpCode.XmlEditor
 			}
 			return false;
 		}
-
-		public bool CtrlShiftSpace(ITextEditor editor)
-		{
-			return false;
-		}
 		
 		bool ElementStartsWith(string text, int elementStartIndex, ITextSource document)
 		{

src/Main/Base/Project/Editor/CodeCompletion/CodeCompletionBinding.cs

@@ -51,7 +51,10 @@ namespace ICSharpCode.SharpDevelop.Editor.CodeCompletion
 		/// </summary>
 		/// <returns>Returns whether the completion binding has shown code completion.</returns>
 		bool CtrlSpace(ITextEditor editor);
-
+	}
+	
+	public interface IInsightCodeCompletionBinding
+	{
 		/// <summary>
 		/// Invokes ctrl-shift-space code insight.
 		/// </summary>
@@ -120,7 +123,7 @@ namespace ICSharpCode.SharpDevelop.Editor.CodeCompletion
 		}
 	}
 	
-	public sealed class LazyCodeCompletionBinding : ICodeCompletionBinding
+	public sealed class LazyCodeCompletionBinding : ICodeCompletionBinding, IInsightCodeCompletionBinding
 	{
 		Codon codon;
 		string[] extensions;
@@ -174,10 +177,12 @@ namespace ICSharpCode.SharpDevelop.Editor.CodeCompletion
 
 		public bool CtrlShiftSpace(ITextEditor editor)
 		{
-			if (MatchesExtension(editor))
-				return binding.CtrlShiftSpace(editor);
-			else
-				return false;
+			if (MatchesExtension(editor)) {
+				var insightBinding = binding as IInsightCodeCompletionBinding;
+				if (insightBinding != null)
+					return insightBinding.CtrlShiftSpace(editor);
+			}
+			return false;
 		}
 	}
 }