[Ide] Remove key press filter that breaks focus chain

Partially fixes VSTS #750236

Author: bratsche

main/src/core/MonoDevelop.Ide/MonoDevelop.Ide.Projects/SelectReferenceDialog.cs

@@ -256,7 +256,6 @@ public SelectReferenceDialog ()
 
 		void InsertFilterEntry ()
 		{
-			filterEntry.KeyPressEvent += HandleFilterEntryKeyPressEvent;
 			filterEntry.Activated += HandleFilterEntryActivated;
 			filterEntry.Changed += delegate {
 				foreach (var p in panels)
@@ -270,15 +269,6 @@ void HandleFilterEntryActivated (object sender, EventArgs e)
 			mainBook.ChildFocus (DirectionType.TabForward);
 		}
 
-		void HandleFilterEntryKeyPressEvent (object o, KeyPressEventArgs args)
-		{
-			if (args.Event.Key == Gdk.Key.Tab) {
-				mainBook.HasFocus = true;
-				mainBook.ChildFocus (DirectionType.TabForward);
-				args.RetVal = true;
-			}
-		}
-		
 		protected override void OnShown ()
 		{
 			base.OnShown ();