1516637 - [Content blocking] The cursor is slightly misplaced inside the “Report a problem” panel with the high contrast set, on Ubuntu 18.04

Status: NEW

(Firefox :: Site Identity, defect, P5)

Description

[Anca Soncutean [:Anca], Desktop Release QA]

Attachment: high contast vs no high contrast.png

[Affected versions]: 
- 65.0b7 (20181227144402)
- 66.0a1 (20181227215704)

[Affected platforms]:
- Ubuntu 18.04 x64

[Steps to reproduce]:
1. Set the high contrast theme (Universal Access - High contrast)
2. Open Firefox with a new profile
3. Go to a webpage that activates Content Blocking
(eg. https://www.reddit.com/)
4. Click the shield icon inside the URL bar
5. Click on the "Report a problem" link
6. Click inside the textarea  placeholder
7. Observe the cursor

[Expected result]:
- The cursor doesn’t change its size or position when the high contrast is activated.

[Actual result]:
- The cursor is not positioned correctly (see the attached screenshot).

[Regression range]: 
- This is not a regression, I could reproduce it way back to Fx 63.0a1 (2018-08-16).

[Additional Notes]:
- Inputted characters are displayed correctly. 
- I can’t reproduce this issue on other textarea placeholders.
- No other platform (including other Ubuntu versions) shown this behavior.