>>> My Info: Win7_64, Nightly 53, 32bit, ID 20161119030204 (2016-11-19) To at least have a chance to convince somebody like Justin Dolske, I had to write 3 scenarios >>> STR_1: (click while paused) 1. Open http://ssyoutube.com/watch?v=s-UFPhz2nZ0 , click "Download", save the video 2. Open the file (saved in Step 1) in a new tab 3. Pause the video 4. Click near the end of the video (~50px from the end) AR: Blue bar in timeline (elapsed time) stops at one position: according to the ratio (Note 1). Scrubber stops at another position: right below mouse pointer. ER: Blue bar and scrubber should be synchronized. Both should respect the ratio requested by the user STR_2: (click while playing) 1. Open http://ssyoutube.com/watch?v=s-UFPhz2nZ0 , click "Download", save the video 2. Open the file (saved in Step 1) in a new tab 3. Skip this step ("Best STR 2016" award�) 4. Click near the end of the video (~50px from the end) AR: Blue bar in timeline stops at one position: according to the ratio (Note 1). Scrubber briefly shows below mouse pointer, then teleports to the same place where blue bar ends ER: Scrubber shouldn't twitch STR_3: (click + accidentally drag) 1. Open http://ssyoutube.com/watch?v=s-UFPhz2nZ0 , click "Download", save the video 2. Open the file (saved in Step 1) in a new tab 3. Skip this step 4. Move mouse near the end of the video (~50px from the end), hold left mouse button, move mouse to the left by ~1px, release left mouse button AR: Blue bar in timeline stops at one position: according to the ratio (Note 1), then it extends to the place where mouse pointer is located. Scrubber follows mouse pointer and doesn't twitch. ER: Blue bar shouldn't twitch. Furthermore, original visual ratio should be respected (ER_total), because user can't expect and predict how exactly video controls will twitch. In more detail: Either X or Y. X is better X) No twitching. Elapsed time should always have the same length as total length. Y) Original length of timeline should be saved as variable L_old. Length from the start of timeline to the mouse pointer on mousedown should be saved as variable L_user. When user holds left mouse button, timeline should shrink (new length should be saved as L_new), but blue line and scrubber should both appear in a well defined point in timeline: L_new*(L_user/L_old) (To reduce complexity, "A/B" here means "A/B if A<B, and 1 if A>=B". "blue line appears in point C" means "the right border of the blue line should have the same horizontal coordinate as point C") AR_total: Timeline shrinks, therefore video seeks to the wrong moment (Note 2) ER_total: Video controls should allow user to rely on visual ratio (Note 1). One way to fix it is to always display the same amount of digits in elapsed time and total time. Another way is to improve mouse handling, so that in such cases only the old length of timeline is accounted. Note: 1) There's no tooltip that would give a hint about the moment in timeline placed directly below mouse pointer, therefore the only way for user to choose some sensible moment is to rely on the visual ratio between total length of timeline and length between the start of timeline and mouse pointer. 2) If user clicks on the point "95% of the video length", he instead ends up at the point like "99% of the video length", because total length of timeline shrinks while length between the start of timeline and mouse pointer stays the same. This is regression from bug 1271765. Regression range: > https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=ec7fb4f14d3ec23ded7eea40ff49ebbcbec6bde1&tochange=8d2eecb7ea5a16e02862dd326ce4519082ce9901@ Ray Lin[:ralin]: It seems that this is a regresion caused by your change. Please have a look.

I think we addressed the same issue in bug 1328060. (scrubber is squeezed by time label...) It's expected that these two bugs can be fixed at once.

Hi Hani, Bug 1328060 has been landed for a while, could you help to verify this bug as I think this issue should be fixed by bug 1328060 as well. Thank you so much :)

Build ID: 20170213030206 User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:54.0) Gecko/20100101 Firefox/54.0 Fixed on on Windows 10 x 64, Mac OS X 10.11 and Ubuntu 16.04 x64 on Firefox Nightly 54.0a1. Please mark this as Resolved Fixed, after that I will change it to Verified Fixed. Thanks.

fix verified

Reproduced on Nightly 2017-01-01. Verified fixed Fx 53b1, Win 10.