Bugzilla

**Note**
* When the user reaches the Customise screen, he will notice 

**Affected versions**
* Nightly v88.0a1
* Beta v87.0b7
* Release v86.0 is unaffected

**Affected platforms**
* MacBook Air 2013; Mac OS 11.2
* not reproducible on MacMini 2011; Mac OS 10.13.6 (probably related to display resolution or aspect ratio)

**Steps to reproduce**
1. Launch browser.
2. Open Hamburger Menu.
3. Click Customize Toolbar...

**Expected result**
* The icons of the Density and Themes buttons aren't overflowing.

**Actual result**
* The icons of the Density and Themes buttons ARE overflowing.

**Regression range**
* I could not investigate for the regressor because mozregression does not work on Mac OS 11.
* It is highly possible this was introduced with Proton code.

**Additional notes**
* MacBook Air 2013 has a display aspect ratio of 16:10, resolution 1440x900.
* MacMini 2011 (most probably) detects the compatible aspect ratio and resolution of the connected monitor; mine has 16x9 and resolution 1920 x 1080.

**Note**
* When the user reaches the Customise screen, he will notice 

**Affected versions**
* Nightly v88.0a1
* Beta v87.0b7
* Release v86.0 is unaffected

**Affected platforms**
* MacBook Air 2013; Mac OS 11.2; display aspect ratio of 16:10, resolution 1440x900.
* not reproducible on MacMini 2011; Mac OS 10.13.6 (most probably) detects the compatible aspect ratio and resolution of the connected monitor; mine has 16x9 and resolution 1920 x 1080.

**Steps to reproduce**
1. Launch browser.
2. Open Hamburger Menu.
3. Click Customize Toolbar...

**Expected result**
* The icons of the Density and Themes buttons aren't overflowing.

**Actual result**
* The icons of the Density and Themes buttons ARE overflowing.

**Regression range**
* I could not investigate for the regressor because mozregression does not work on Mac OS 11.
* It is highly possible this was introduced with Proton code.