It would also be handy to have an isSliding property. I'm building the seek-bar for a media-player control, which has a time-display and a seek-bar. Time ticks along as the video plays. However, if I drag the slider handle to seek, I want the time-display to show where the video would start playing from if I release the mouse-button. While I'm sliding, I don't want the time-display to update; that would spoil the UI a bit.
So, I'm trying to make a kind of mutex in my own code to prevent this, and it works well. I grab the mutex in the slide eventhandler, and release it in the stop eventhandler. However, now, if I click in the bar to seek to where the mouse is, the mutex is grabbed but not released, because the stop eventhandler does not fire.