Unable to find and remove the fifth label from label list

**Is your feature request related to a problem? Please describe.**
Can't find the fifth label when I hit the minus symbol on the label list sub panel.

Turns out that the display was scrollable.

**Describe the solution you'd like**
A visible bar that would indicate scroll ability when there are more than 4 labels in the label list.

**Describe alternatives you've considered**
An arrow that points down to the hidden labels.

**Additional context**
Steps to reproduce:
1. Create new project.
2. Add 5 labels.
3. Use the remove button to remove the fifth label.

OS: Windows 10

Start at the label list sub panel and reproduce the steps with five labels. The work is done when the list visibly indicates that more labels can be scrolled to and the fifth label can be removed without guessing that hidden items exist.

Written by the indexing model from the issue text.