Welding, Points

[geh55]

Hi
I'm new here and can't speak English (translated with google translator).
I bought Moho 12 pro to do small animations. Unfortunately, even the simplest things do not work. The lasso mode does not work properly when marking points. If I activate the mouse in the middle, the line is shown offset at the top left. No matter where the mouse is, the distance to this line is always the same.
The welding does not work either. Put two shapes on top of each other, mark points and then click seam intersection, nothing happens. Viewed in several tutorials and still it doesn't work for me.
Program already uninstalled several times, does not work.
Who can help. Many Thanks