Specifically using the left and right arrow keys to skip back/ahead 5 seconds. These hotkeys work when you are in the options menu (they also are navigating through the menu) or when you click on a node that brings up no data, but as soon as you have songs/entries in your list pane the keys stop effecting playback and only navigate. Even when clicking on the player itself. These keys were set to 'global' and work whenever the player is not the 'active' window. This seems to be a new development since installing 4.0.0.1353.

Using Windows 7 Ultimate