(Apologies if this is in the wrong forum)
I know this isn't really within GPS's remit, but I would pay money for a DOpus plugin that played selected audio files in a playlist. I can dream.
Most MP3 players add an Enqueue option to the right-click menu, or let you select multiple files and push enter or drag them to the player.
...or have a commandline to create own buttons/menus for that (and more).
Command line buttons - that's interesting, thanks
Here's an example for a toolbar incl. icons (controlling only, I prefer creating playlists within the player itself, using AIMP):
Very nice icon set, I like it.