Dear Xara...

...this Bug was previously sorted but it seems you missed an edge case.

Create any two Shapes.
Give both a Contour.
Apply Soft Group.
Bug: You now cannot Remove Soft Group.

This occurs with any number of contoured shapes.
Remove the contour from any one and you can remove the Soft Group.
Add in a non-contoured shape and you can remove the Soft Group.

Acorn