Bugzilla

**[Affected versions]:**
- Firefox Nightly 89.0a1, Build ID 20210324160546

**[Affected Platforms]:**
- Windows 10
- macOS 10.15
- Ubuntu 20.04 (with `general.autoScroll` set to `true`)

**[Prerequisites]:**
- Have a new Firefox profile.

**[Steps to reproduce]:**
1. Open the browser with the profile from prerequisites.
2. Navigate to the about:support page.
3. Initiate an autoscroll event using the middle mouse button (scroll) and move the mouse down.
4. Observe the behavior

**[Expected results]:**
- The page is scrolled downwards.

**[Actual results]:**
- Autoscroll is not triggered in the page.

**[Regression Window]:**
 2:52.86 INFO: Last good revision: 630002d187a1f7c9a7c61dcf4b8fc110698b665b
 2:52.86 INFO: First bad revision: 8fcec4a428e2b9b6595c69511aae4429881d0c52
 2:52.86 INFO: Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=630002d187a1f7c9a7c61dcf4b8fc110698b665b&tochange=8fcec4a428e2b9b6595c69511aae4429881d0c52

From the pushlog it looks like bug https://bugzilla.mozilla.org/show_bug.cgi?id=1686662 has caused this.
@masayuki, could you please take a look at this?

**[Notes]:**
- The issue is also reproducible on the about:preferences, about:addons, about:telemetry pages
- Attached a screen recording of the issue.

**[Affected versions]:**
- Firefox Nightly 89.0a1, Build ID 20210324160546

**[Affected Platforms]:**
- Windows 10
- macOS 10.15
- Ubuntu 20.04 (with `general.autoScroll` set to `true`)

**[Prerequisites]:**
- Have a new Firefox profile.

**[Steps to reproduce]:**
1. Open the browser with the profile from prerequisites.
2. Navigate to the about:support page.
3. Initiate an autoscroll event using the middle mouse button (scroll) and move the mouse down.
4. Observe the behavior

**[Expected results]:**
- The page is scrolled downwards.

**[Actual results]:**
- Autoscroll is not triggered in the page.

**[Regression Window]:**
 2:52.86 INFO: Last good revision: 630002d187a1f7c9a7c61dcf4b8fc110698b665b
 2:52.86 INFO: First bad revision: 8fcec4a428e2b9b6595c69511aae4429881d0c52
 2:52.86 INFO: Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=630002d187a1f7c9a7c61dcf4b8fc110698b665b&tochange=8fcec4a428e2b9b6595c69511aae4429881d0c52

From the pushlog it looks like bug https://bugzilla.mozilla.org/show_bug.cgi?id=1686662 has caused this.
@masayuki, could you please take a look at this?

**[Notes]:**
- The issue is also reproducible on the about:preferences, about:addons, about:telemetry pages.

**[Affected versions]:**
- Firefox Nightly 89.0a1, Build ID 20210324160546

**[Affected Platforms]:**
- Windows 10
- macOS 10.15
- Ubuntu 20.04 (with `general.autoScroll` set to `true`)

**[Prerequisites]:**
- Have a new Firefox profile.

**[Steps to reproduce]:**
1. Open the browser with the profile from prerequisites.
2. Navigate to the about:support page.
3. Initiate an autoscroll event using the middle mouse button (scroll) and move the mouse down.
4. Observe the behavior.

**[Expected results]:**
- The page is scrolled downwards.

**[Actual results]:**
- Autoscroll is not triggered in the page.

**[Regression Window]:**
 2:52.86 INFO: Last good revision: 630002d187a1f7c9a7c61dcf4b8fc110698b665b
 2:52.86 INFO: First bad revision: 8fcec4a428e2b9b6595c69511aae4429881d0c52
 2:52.86 INFO: Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=630002d187a1f7c9a7c61dcf4b8fc110698b665b&tochange=8fcec4a428e2b9b6595c69511aae4429881d0c52

From the pushlog it looks like [bug 1686662](https://bugzilla.mozilla.org/show_bug.cgi?id=1686662) has caused this.
@masayuki, could you please take a look at this?

**[Notes]:**
- The issue is also reproducible on the about:preferences, about:addons, about:telemetry pages.