Polygon Multi-Select not working on MacOS 11

[Alexandru Muresan]

Describe the bug
When trying to select multiple polygons to copy and paste on the next frame only one polygon remains selected and copied.

To Reproduce
Steps to reproduce the behavior:

1. Create a new project
2. Adnotate multiple objects
3. Hold shift and click on multiple polygons
4. Copy
5. Paste on the next frame
6. Only the last clicked polygon is pasted

Expected behavior
All the clicked polygons should be selected, copied and pasted over to the next frame

Desktop (please complete the following information):

• OS: MacOS 11.6.1
• Version: VoTT 2.2.0 (local, installed from .dmg file)