add alt popup window style allowing to use keyboard and comboboxes in the popup window and use it for the generic date picker (patch 1582391 from Jaakko)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@42247 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/popupcmn.cpp

@@ -561,7 +561,7 @@ void wxPopupFocusHandler::OnKillFocus(wxFocusEvent& event)
 void wxPopupFocusHandler::OnKeyDown(wxKeyEvent& event)
 {
     // let the window have it first, it might process the keys
-    if ( !m_popup->ProcessEvent(event) )
+    if ( !m_popup->GetEventHandler()->ProcessEvent(event) )
     {
         // by default, dismiss the popup
         m_popup->DismissAndNotify();