Bugzilla

**Affected versions**
* Nightly 71.0a1
* Firefox 70.0b5

**Affected platforms**
* Windows 7 x64
* Ubuntu 18 x64
* macOS 10.12

**Prerequisites:**
- Install add-on so that the scroll bar appears on the about:addons page.

**Steps to reproduce**
1. Click on one of the add-on and scroll down the page. 
2. Click on the "Go back" button.
3. Observe the scroll bar. 

**Expected result**
* The scroll bar on the about:addons page is at the top of the page. 

**Actual result**
* The scroll bar is at the bottom of the page. 

**Regression range**
* It's a regression, I can reproduce the issue using Nightly from 2019-05-02. I will find a regression asap. 

**Additional notes**
* Please look at the attached video.

**Affected versions**
* Nightly 71.0a1
* Firefox 70.0b5

**Affected platforms**
* Windows 7 x64
* Ubuntu 18 x64
* macOS 10.12

**Prerequisites:**
- Install add-on so that the scroll bar appears on the about:addons page.

**Steps to reproduce**
1. Click on one of the add-on and scroll down the page. 
2. Click on the "Go back" button.
3. Observe the scroll bar. 

**Expected result**
* The scroll bar on the about:addons page is at the top of the page. 

**Actual result**
* The scroll bar is at the bottom of the page. 

**Regression range**
* It's a regression, I can't reproduce the issue using Nightly from 2019-05-02. I will find a regression asap. 

**Additional notes**
* Please look at the attached video.