When Right click on the folder and select "play in foobar2000",
send them to a new playlist and name the playlist with the folder's name.
I think it will be better!
Sorry, I have made a mistake, the word "forder" in the topic should be "folder".
That's not a bad idea. Currently, I either empty out the current playlist or make a new playlist and then selecting the context-menu option "Play in foobar2000."