When I go to change the color of some text in the text editor, the color picker just disappears when I interact with it at all. When I choose a color or when I drag the modal out of the way. Please see this demo:
https://monosnap.com/file/LVOBHaxB6LwKwEuQHpvVUn5APu0rBY
Can you see if you can duplicate the issue on your install?