Chroma Visualizer no longer working correctly

I have chroma visualizer set so that it syncs my lighting with windows media player. However, on playing music via WMP today, it only works while windows media player is maximized. If I minimize WMP, the visualizer stops. Previously, it carried on running as long as windows media player was running, even when minimized. Is this an intended change, or has something gone wrong? I have tried doing a repair install of Synapse, but it's made no difference.