instantiating a new canvas

Hello

I have a project, and I make use of the Relationalframes canvas by Alex Restrepo.
Now, I the user makes a new project, all data must be cleared. I try that this way:

BlocksCanvas = New RelationalFrames.RelationalFramesCanvas

With other objects I use, this works fine (obviously)
But in this line of code, I got an error

And the “BlocksCanvas” is marked in yellow.
Now, I’m pretty sure it does exist. What do I do wrong?

Proof:

Thanks in advance
Edit: I did found another option to use, I redimmed the array that holds the frames in the Relationalframes class. But my question still stands. I have no idea where the compilationerror is thrown.