Splasm Software Discussions

I'm trying to rearrange a couple of out-of-sequence files prior to building an audiobook, and the keyboard shortcut doesn't seem to be working. Is there a problem with the keyboard shortcut? I'm running Audiobook Builder 2.0.1.236 on a 2012 MacBook Pro running MacOS 10.12.6 Sierra. I can get this done by right-clicking on the file and selecting "Move Up" from the menu, but this is tedious and a working keyboard shortcut would make this task much less "painful." Thanks for any assistance anyone can provide.