You may find that some player elements open behind web objects. This can happen with the volume slider and any drop-down menus you've added to the top left or top right of the player, such as menu, resources, glossary, or custom tabs.
This also affects videos inserted from websites (Screenr, Vimeo, Google Videos, etc) and imported Engage interactions, since these are also treated as web objects. (One notable exception is YouTube. YouTube videos inserted via Video from Website are wrapped in a Flash control, so they won't experience this issue.)
This is a known issue. Unfortunately, there is currently no workaround. When additional information becomes available, we'll post it here.