1. modified wxMSW::wxCaret to use client coords

2. fixed uninit m_curXXX vars leading to a crash in wxMSW
3. fixed wxWindow::DoDrawBackground() for empty update region


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/wxUNIVERSAL@8406 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/univ/winuniv.cpp

@@ -205,6 +205,13 @@ void wxWindow::OnPaint(wxPaintEvent& event)
 bool wxWindow::DoDrawBackground(wxDC& dc)
 {
     wxRect rect = GetUpdateRegion().GetBox();
+    if ( !rect.width && !rect.height )
+    {
+        wxSize size = GetSize();
+        rect.width = size.x;
+        rect.height = size.y;
+    }
+
     if ( GetBackgroundBitmap().Ok() )
     {
         // get the bitmap and the flags