Hi,
the help text displayed in the bottom line is missing relevant details and seem slightly misleading.
To set the origin, you need to double-click.
Click alone has no effect. Click AND drag (not click OR drag) will drag the point of origion.
Recommendation for help text:
Double-click to set origin, or click-drag to move origin.
Help documentation / persistent variables
The procedural texture help documentation could be improved, e.g. by adding a chapter to list all available "persistent variables" and their definitions.
ox and oy is currently not mentioned at all in help (only listed in the UI bottom line)
The values have been investigated by trial & error. It would be great to get them confirmed or corrected by the devs.