(Sequence Diagram) How do I remove the dotted line from OPT fragment in Visual Paradigm?

I am trying to make an OPT fragment in Visual Paradigm for my Sequence Diagram. I did this by creating an ALT fragment, then changing its Interaction Operator Kind to OPT. However, the stubborn dotted line refuses to be removed. Any guidance appreciated.

When the combined fragment having more than one operand then it will show the dotted line(s). You can right click on the header of the combined fragment and select Operand > Remove Operand to delete the unused operand. You can also select Manage Operands... from the popup menu to bring the Manage Operands dialog for review the details of each operand in order to determine which one should be removed. As long as the combined fragment having just one operand then it will not show the dotted line.