>>> My Info: Win7_64, Nightly 47, 32bit, ID 20160225030209 STR: 0. Set mouse option "when I rotate mouse wheel" in your OS to "scroll by 1 page" 1. Open many tabs to cause overflow in Tabs Toolbar 2. Let say you got N fully visible tabs in tabs toolbar. 3. Open attached "testcase 1" in a new window, type N in <input> on that page, click the button. (If popup windows are prohibited, allow them, then click the button again) 4. Scroll tabs list to the beginning 5. Hover mouse over the 1st tab 6. Rotate mouse wheel down once AR: Tabs list is scrolled to the end. ER: Tabs list should be scrolled by ~N tabs to the right Note: On the normal pages, rotating mouse wheel down scrolls the page by visible amount of lines. So if similar functionality is presented in Tabs Toolbar, I expect it to work the same way. Currently if I scrolled tabs list to the beginning and want to select the 2*N th tab, I have to hover mouse over the right scrollbutton, hold left mouse button and spend much time to scroll tabs list to the 2*N th tab.
This was regressed even more after bug 1263975. And I won't report a new bug for the same thing.
Not tracking for 47, since this seems to be an old regression (albeit it one recently made worse?).
Created attachment 8749304 [details] [diff] [review] patch
Arni, how is this in nightly now? I can try going through the other bugs you mention in "see also". We also could uplift this fix to aurora 48 if it's verified fixed in 49. Too late for 47 uplift though.
Markus, want to request uplift to aurora? If you think it's not too risky that is.
Comment on attachment 8749304 [details] [diff] [review] patch Approval Request Comment [Feature/regressing bug #]: has always been broken, but bug 1263975 made it even more broken (before bug 1263975, scrolling was way too fast, after bug 1263975 scrolling was way too slow) [User impact if declined]: Windows users who have the scroll wheel system setting "Scroll by 1 page" will experience very slow scrolling in the tab bar and in scrollable menus, like the tab list dropdown. [Describe test coverage new/current, TreeHerder]: I did a fair amount of manual testing. automated test coverage is low - there is one existing test that checks that scrolling the affected elements scrolls in the right direction, but no test that makes sure that we scroll by one page. [Risks and why]: low - There's not much that can go wrong and I tested it locally. If there are bugs in the patch then only users with this (admittedly rather exotic) system setting will be affected, and it can't get much worse than without this patch [String/UUID change made/needed]: none
Comment on attachment 8749304 [details] [diff] [review] patch Tested manually, has been in m-c for a while, let's uplift and verify in aurora.
>>> My Info: Win7_64, Nightly 49, 32bit, ID 20160522030240 I don't see any problems with scrolling tabs with mouse option set to "scroll by 1 page", for the first time in 5 years I'm using the browser (compare comment 0 and comment 3). Rotating mouse N times results in [scroll by visible amount of tabs] performed N times. Note that I have NOT tested it with extensions that change tab witdh, e.g. "FaviconizeTab". (In reply to Liz Henry (:lizzard) (needinfo? me) from comment #9) > I can try going through the other bugs you mention in "see also". You're right, I mentioned several bugs in comment 2, but they are unrelated now. To get more info about Firefox breakage resulting in many sites being unusable for many years, read (whole) bug 1257815