Cannot Right Click Media Items -- Help

[GEC]

I can't right click media items to open the context menu -- I have to use the overhead menu to get there. I've referenced these previous threads and neither has helped.

https://forum.cockos.com/showthread.php?t=201057
https://forum.cockos.com/showthread.php?t=168888

I'm running 64-bit Windows. I've tried downloading the latest versions of both Reaper and SWS, restarting, using different mouses, going Options -> Customize Menus/Toolbars to check on the Media Item Context menu. Nothing seems to be out of the ordinary. When I right click a media item, the item deselects. If I double right click or click right and left, I get a global context menu, not an item context menu.

Any ideas would be greatly appreciated