added wxDialog::GetParentForModalDialog() and use it to try to always create modal dialogs with a parent (slightly modified patch 1702962)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@45588 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/msgdlgg.cpp

@@ -64,6 +64,8 @@ wxGenericMessageDialog::wxGenericMessageDialog( wxWindow *parent,
 {
     SetMessageDialogStyle(style);
 
+    parent = GetParentForModalDialog(parent);
+
     bool is_pda = (wxSystemSettings::GetScreenType() <= wxSYS_SCREEN_PDA);
 
     wxBoxSizer *topsizer = new wxBoxSizer( wxVERTICAL );