Check if colour really changed in wxGenericListCtrl::SetBackgroundColour().

Call the base class version to update the colour stored in the base class and
also to avoid changing the colour of the main window unnecessarily if the
colour didn't really change.

This is also consistent with the code in SetForegroundColour() just below.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@75328 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/listctrl.cpp

@@ -5197,6 +5197,9 @@ void wxGenericListCtrl::OnInternalIdle()
 
 bool wxGenericListCtrl::SetBackgroundColour( const wxColour &colour )
 {
+    if ( !wxWindow::SetBackgroundColour( colour ) )
+        return false;
+
     if (m_mainWin)
     {
         m_mainWin->SetBackgroundColour( colour );