Define lower right corner of box by selection

What causes this issue?

When you create a box, the position of the beginning of the group box
text and the position of the cursor determine the opposing corners of
the rectangular area.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Place the cursor so that the edges of the box do not overlap with other
screen elements and then choose <LS>Select block end</>.

Error message extract from SAP system. Copyright SAP SE.