User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040614 Firefox/0.9 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040614 Firefox/0.9 Autoscroll (clicking the middle mouse button and moving the mouse) performance is much slower and jerkier than other forms of scrolling on the same page, including using the scroll bar, or rolling the mouse wheel. This has been discussed before and if I recall correctly I believe that it may have been blamed on the partially transparent icon that is visible during autoscroll. I believe the performance was improved a bit a couple of versions ago. However, the performance is still significantly poorer than using the scroll bar, so there is still something wrong. Reproducible: Always Steps to Reproduce: 1. Autoscroll on a web page, particularly a long one like the example URL Actual Results: Significantly slower and jerkier than using the scroll bar, or using the mouse wheel. Expected Results: Smooth and fast scrolling. If this problem really is due to the semi-transparent autoscroll icon, then this could be indicative of poor performance in general of rendering semi-transparent images and moving them. In that case the problem would be due to rendering speed, but a workaround would be not to use a semi-transparent icon for the autoscroll icon. Unfortunately, the dreaded MSIE autoscrolls much more smoothly on the same pages.

Works fine for me in Firefox 0.8.

(In reply to comment #1) > Works fine for me in Firefox 0.8. The issue is not whether it works or not; the issue is that it works, but the performance is very slow, which causes it to be very jerky. Compare it with the smoothness of using the scroll bar.

(In reply to comment #2) > (In reply to comment #1) > > Works fine for me in Firefox 0.8. > > The issue is not whether it works or not; the issue is that it works, but the > performance is very slow, which causes it to be very jerky. Compare it with the > smoothness of using the scroll bar. By "works fine" I mean it works as expected, not slow as you report.

Moving to FF b/c to my knowledge Mozilla doees not have Autoscroll feature w/o an extention.

Here's some updated 'steps to reproduce' for this bug: 1. Go to http://www.zeldman.com/daily/0604d.shtml 2. Slowly move the page up and down using the scroll bar at the right hand side of the page with your mouse. Notice how smooth the movement is. 3. Click the page with your middle mouse button so that the translucent autoscroll icon appears (if it doesn't or if it's not translucent, then your mouse driver is overriding it - turn that off). 4. Slowly move your mouse up and down and see how smooth the movement is. 5. Compare the two movements. Actual result: Scrolling with autoscroll is significantly jerkier (many times over) than using the scroll bar. Noticeable but less annoying on a newer computer (Athlon XP 2600+). Extremely annoying on older computer (Athlon Thunderbird 900). Expected result: Scrolling with autoscroll is just as smooth as using scroll bar. --- Note: Moving the autoscroll icon out of the DOM will render this bug irrelevant, and likely solve the problem. Therefore I would recommend that this bug depends on bug #242621.

This is partially due to using a semitransparent icon, but probably mostly caused by having the autoscroll icon in the DOM. Only noticible on slower machines.

It's particularly annoying on slower machines, but it's quite noticeable on all machines. It's noticeable on the following computer for me: Athlon XP 2600+ ATI Radeon 9600 128Mb Windows XP 512 Mb RAM

*** Bug 263894 has been marked as a duplicate of this bug. ***

I noticed that right away after installing. On my PC the CPU usage reaches 95 %. Especially when using "AutoScroll" for scrolling left, right and diagonally (coz of sidebar or ICQ, for example), it's very jerky. Scrolling up and down is absolutely no problem, so I dont think the reason is the semi-transparent icon. I use the following PC: Athlon XP 2400 Radeon 8500 64m WinXP Pro (already reproduceable on 9x) 512m RAM In IE the movement of the page is smooth, even if you scroll diagonally.

*** Bug 283700 has been marked as a duplicate of this bug. ***

In Firefox 1.0.6, autoscroll performance doesn't change. autoscroll is much slower. In deer park alpha 2, it's the same problem.

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b5) Gecko/20050929 Firefox/1.4 ID:2005092911 It's still slow on sites that use PNG graphics and/or some fix/absolute positioned elements. It's actually due to the autoscroll marker (which is PNG, I suppose). One can disable it with the All-in-One Gestures extension (0.17.2, Advanced Prefs #2). Furthermore, setting the Autoscroll Refresh Rate to Faster makes scrolling entirely smooth. Maybe these options should be set by default or at least be part of some "Advanced -> Performance" options window. Otherwise someone should fix the marker.

(In reply to comment #12) > It's actually due to the autoscroll marker (which is PNG, I suppose). One can > disable it with the All-in-One Gestures extension (0.17.2, Advanced Prefs #2). > Furthermore, setting the Autoscroll Refresh Rate to Faster makes scrolling > entirely smooth. Just to address your comment: Removing the autoscroll marker has no noticeable difference for me. I guess that some graphics subsystems can cope with the autoscroll marker better than others. Mine has no problem. Setting the Autoscroll Refresh Rate to faster in All-in-One Gestures does significantly help the problem for me in simple pages, but does not help on more complex pages such as those with fixed elements, frames, applets etc. In these cases, using the scroll bar is always significantly smoother than autoscroll. The benchmark for this is the scrollbar - autoscroll should, in my opinion, be as smooth in motion as using the scrollbar - there is no reason it should be different. This obviously depends on the other bugs mentioned in meta bug #212273.

As a user of both windows and Linux, I'd like to make sure everyone realizes that this bug is windows specific. I have both Win XP and Ubuntu on the computer I'm using, and the difference is very noticeable, both in terms of CPU usage and performance.

(In reply to comment #14) > As a user of both windows and Linux, I'd like to make sure everyone realizes > that this bug is windows specific. I have both Win XP and Ubuntu on the > computer I'm using, and the difference is very noticeable, both in terms of CPU > usage and performance. > I'm not sure if 1.5 had anything to do with this, but I'm using the RC right now in Windows, and it seems to perform as expected. I'm not going to get 1.07 just to compare right now, but maybe this will still be useful. If needed, I can compare it on request.

Firefox 1.5 RC 1 : autoscroll is still slow with almost pages. There are a little amelioration than 1.0.x. With All In One Gestures extansions which can put more faster the fresh rate, the problem can be resloved. Note concerning All In One Gestures : the semi transparent icon can be deleted with this extansion but i didn't see ant differences after that.

I randomly had my task manager open. Autoscroll a page up and down, CPU is almost full. Scroll wheel or scroll bar only goes to half CPU.

I've noticed using the lastest branch builds that AutoScroll (Smoothscrolling disabled) is VERY jerky (seen on machines with both nVidia and ATI cards) on pretty much every page, even more so then 1.x. This seems to have worsened in the latest builds. Can we get this fixed once and for all? BUILD: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8) Gecko/20060502 BonEcho/2.0a1 ID:2006050201 ~B

Autoscroll works fine for me with recent branch builds.

not a blocker, would be glad to take a patch

This should be significantly better with my checkin for bug 242621. With the layout debugger, it is apparent that significantly less of the screen is repainted during scrolls now.