As the title said, I cannot open the curve edit panel in all my projects. I don’t know whether it is just my problem or is a bug.
Do you have an browser extensions installed?
I don’t think there is anything directly related to playcanvas…but I can open this panel when I browse in incognito mode, strange… 
Anyway, I can still use it now, thank you for your help 
Interesting. I would try deleting cache and cookies for PlayCanvas and see if it still happens.
If it does, there might be an error in the browser Dev console.