I tried those buttons also... imho they stand for Loop, Bounce, 1 time play (play once)...
strange, because they use standard icons elswhere in the program... but maybe i'm missing something
desktop: Windows 7 home premium 64 bit, MSI 870A-G54, AMD Phenom II X4 955 Black Edition, 4Gb RAM (GVP34GB1600C9DC), NVidia GTX 560
laptop: Windows 7 home premium 32 bit, Core2duo 2Ghz, 4Gb Ram, NVidia 9600m GT
Yea makes sense but not sure if it works. In the timeline mode for the clip the standard (version 2) icons appear and the I can set the clips to bounce but when set to BPM (with the new B, L etc icons) it repeats looping. Hmmmm.