Blind guess fix for wxRB_SINGLE

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@56202 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/radiobut.cpp

@@ -66,7 +66,7 @@ bool wxRadioButton::Create( wxWindow *parent,
     }
 
     GSList* radioButtonGroup = NULL;
-    if (!HasFlag(wxRB_GROUP))
+    if (!HasFlag(wxRB_GROUP) && !HasFlag(wxRB_SINGLE))
     {
         // search backward for last group start
         wxWindowList::compatibility_iterator node = parent->GetChildren().GetLast();