workaround to fix geometry update when drawing on desktop (ubuntu 18)

src/desktop/UBDesktopAnnotationController.cpp

@@ -903,6 +903,10 @@ void UBDesktopAnnotationController::updateMask(bool bTransparent)
         }
 
 #ifdef Q_OS_LINUX
+        // workaround required for Ubuntu 18 (issue : drawing is not visible in Desktop Mode until updateMask is recalled)
+        QRect desktopRect = QApplication::desktop()->screenGeometry(mDesktopPalette->pos());
+        p.drawRect(desktopRect);
+
         //Rquiered only for compiz wm
         //TODO. Window manager detection screen