Element is too long (visible field length will be shortened)

What causes this issue?

You have increased the visualized (visible) length of an input/output
field which has the attribute "scrollable".
This is not allowed either because, to the right of the element, there
is another element (e.g. field text, input/output field, graphical
element, subscreen) which would be truncated or moved, or because the
right edge of the screen has been reached.

System Response

Length increased only to maximum allowed.

How to fix this error?

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

Error message extract from SAP system. Copyright SAP SE.