You can share your screen using Firefox.
As browsers are updating so often to keep up with new features and security improvements, we highly recommend you use the latest version available.
For Firefox, you can find that here.
How to share your screen on Firefox:
1. Click the Add '+' icon on the right of the classroom
2.Click Start sharing
3. Choose the screen you'd like
4. Click Allow
This will share the screen you selected inside the LearnCube whiteboard.
5. When you're ready to stop, simply click the x icon and close the whiteboard tab.