Resolves: tdf#94069 call setVisible when setDesignMode is called

void UnoControl::setDesignMode calls setVisible on the XWindow
so it seems sensible that FmXGridPeer::setDesignMode should
also do so. The desirable side effect is that moving the window
in design mode then is moving a un-shown window so nothing
is invalidated so the paint loop doesn't happen.

Change-Id: Ic5a4ba62590372bec15a29b993b73d6dfb94a8a9

svx/source/fmcomp/fmgridif.cxx

@@ -1693,6 +1693,8 @@ void FmXGridPeer::setDesignMode(sal_Bool bOn) throw( RuntimeException, std::exce
             static_cast<FmGridControl*>(pWin)->SetDesignMode(bOn);
     }
 
+    setVisible(!bOn);
+
     if (bOn)
         DisConnectFromDispatcher();
     else