It appears to me that in the 11/24/2016 nightly (and I think also in the official Ubuntu pre-built 2.6.15) when you mouse left-click on some position on the timeline that's either to the left or to the right of the current timeline cursor, the timeline cursor is only moved a little bit, either to the left or to the right, almost as if you had instead clicked on either the << or >> control buttons near the bottom of the Avidemux window. This behavior is counter-intutive. I think it would be preferable if clicking some spot on the timeline would cause the timeline cursor to move all the way to the place clicked on. (If the user just wants to move the timeline cursor just a little bit, then he can use the << or >> or > or < buttons instead.)
You are aware when selecting slider knob and keep it selected you can drag (left/right) to any position very fast.
See small demo on our YouTube channel: Avidemux Demo, fast forward in 720p 5 1/2 hour video (https://www.youtube.com/watch?v=LcUGtoHHmXg) 1.15 minutes.