Anton,
I DM'd you a skp file and screen capture of what happens. It happens with all SKP files no matter how complicated or simple. At first I thought maybe the geometry I was using was too complicated but you can see with that simple file simple draping does not work for me. This file used a quadrilateral grid at 3000 and default settings. I've uninstalled CW and reinstalled it. Versions of my software are:

OSX Mojave Version 10.14.5
sketchup Version 19.2.221
ClothWorks version 1.7.0a

I've been using this extension for some time now but I currently have an issue. Clothworks is crashing when ever I go to drop a cloth over a 3d item. Single plane it has no issue, but if there are 2 or more angels outside of the one plane it crashes with no warning, or lag.