What does the orange bouncing thing in the progress bar in VLC mean?

It's the animLoading bouncing thingy caused by a

animLoading->start();

without a matching

animLoading->stop();

which usually doesn't happen when the video is started, but it's on all the time bouncing for any subsequent videos in the playlist while they are playing.

to workaround this bug, I just commented out that start line (245) in

modules/gui/qt4/util/input_slider.cpp