Min Vid overlay overlaps website's toolbar on Youtube (new UI) and Vimeo

[SoftVision-CarmenFat]

[Affected versions]:

• Firefox 55.0.3 and up
• Min Vid v.0.4.4

[Affected Platforms]:

• All Windows
• All Mac
• All Linux

[Prerequisites]:

• Latest Min Vid add-on version (0.4.4) was previously installed on a clean profile.

[Steps to reproduce]:

1. Open the browser with the profile from prerequisites and navigate to YouTube (www.youtube.com/new).
2. Click on one of the videos.
3. While hovering the player, scroll down slowly.
4. Observe the website's toolbar while scrolling down the Min Vid overlay.

[Expected result]:

• The Min-Vid overlay is hidden under the toolbar.

[Actual result]:

• The Min-Vid overlay overlaps website's toolbar.

[Notes]:

• On Youtube's old UI this issue is not reproducible.
• Please see the following screencast of the issue:

[meandavejustice]

fixed in https://github.com/meandavejustice/min-vid/commit/938a1cbf8ecf0fa44e375c6497bf4bad7376dfb2

[SoftVision-CarmenFat]

• Tested this with latest Min Vid v.0.4.5 (built on 9/26/2017) and I can confirm that Min Vid's overlay is not overlapping Youtube's toolbar anymore.
• However, the issue is still reproducible on Vimeo's Homepage.