I wanted to make a manipulate where an ellips is moving if I move a point (p1 and p2). I calculate in a function the ellips and some points of it and return points in a list. The input values of the function are the variables of the manipulate. I tested the function before, everything seems OK. If I use the list of points (I hope they are dynamical) in the manipulate (the last in the notebook) the kernel crashes. I have a error message: An unknown box name (ToBoxes) was sent as the BoxForm for the expression. Check the format rules for the expression.

I added a notebook with comments. I hope someone will have the time to look. I tried already a couple of days.

Many thanks. Wiel