Category Picker Scrollbar is broken on scaled UI at 150% or at a smaller browser height

[GeekInTheNorth]

We have found an issue opening the Geta Categories picker where the page already has multiple selected categories. This issue affects smaller brower windows and normal desktop windows were scaling is in use such that the effective or scaled viewport is 620 pixels or less.

Browser: Chrome, HD Desktop, Zoom at 150% or Larger
Browser: FireFox, HD Desktop, Zoom at 160% or larger
Browser: Chrome, View Height <620 pixels
Browser: FireFox, View Height <620 pixels
Category Tree:

• For All Sites
  • Content Types
    • Blog
    • Event
    • News
    • Offer
  • Rooms
    • Duplex
    • Penthouse
    • Suite
    • Standard
  • Topic
    • Celebration
    • Conference
    • Luxury Break
    • Wedding

Steps to Reproduce Based on Chrome and 150% zoom, On FireFox this happens at 160%:

1. Assign a Sub Category from under each top level category to your page and publish it.
2. Open the Category Picker with your browser zoom to 100% or 125% - Note that the scrolling works as expected.
3. Open the Category Picker with your browser zoom at 150% or larger - Note that the scrolling does not work and parts of the category tree cannot be clicked

Steps to Reproduce based on limited View Height

1. Open the browser at full screen height
2. Assign a Sub Category from under each top level category to your page and publish it.
3. Resize the browser window so the view port is less than 620 pixels in height e.g. like a smaller laptop or tablet. Note that the scroll bar does not work.
4. Resize the browser window so the view port is 620 pixels or greater. Note that the scrolling does not work and parts of the category tree cannot be clicked

[GeekInTheNorth]

Updated the issue as this is not specific to zoom levels, but to viewport height with no zoom.