I'm using a TabTop MLR and I want to set the background colour but nothing I do seems to work - It always behaves transparent and shows the underlying colour/texture of the page or layout region. There seems to be an option to change the background of the MLR or individual pages but nothing changes. I notice there is a little lock icon in the top left corner of the Properties window. How do I unlock the MLR? Will that make the difference? (The Style is unlocked).