finally fixed the flicker problem in wxTE_RICH[2] text controls when appending a lot of text to them

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@19314 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/textctrl.cpp

@@ -914,6 +914,14 @@ void wxTextCtrl::SetInsertionPoint(long pos)
 
 void wxTextCtrl::SetInsertionPointEnd()
 {
+    // we must not do anything if the caret is already there because calling
+    // SetInsertionPoint() thaws the controls if Freeze() had been called even
+    // if it doesn't actually move the caret anywhere and so the simple fact of
+    // doing it results in horrible flicker when appending big amounts of text
+    // to the control in a few chunks (see DoAddText() test in the text sample)
+    if ( GetInsertionPoint() == GetLastPosition() )
+        return;
+
     long pos;
 
 #if wxUSE_RICHEDIT