Open Roberta Sim: Add colour area button flickers

[AHberta]

Describe the bug
In the simulation, the button for adding a coloured area flickers, if the mouse pointer is on the button. The same problem also exists with the button for adding an obstacle.

To Reproduce
Steps to reproduce the behavior:

1. Go into Sim
2. Move the mouse to the "Add a colour area" button - button flickers
3. Move the mouse to the "Add an obstacle" button - button flickers

Screencast

https://github.com/OpenRoberta/openroberta-lab/assets/19265064/2506b3f6-86c0-4523-a1b7-14040064169c
Unfortunately not visible in the screencast

Device information

• System: Open Roberta Sim
• OR: test.open-roberta.org
• Type Laptop
• OS: Windows
• Browser Edge