Synthetica V2.9 (Swing Look and Feel) comes along with a new theme called Synthetica BlackEye Look and Feel. Below you'll find a short summary of the most important highlights.
Generally in Swing you can specify the paint order by applying component Z-Order (see Container#setComponentZOrder). This method is useful as long as you're using a null layout or a layout manager which makes use of constraints.
The disadvantage of using #setComponentZOrder is that it can affect component position.