‘8va’ text keeps coming back

Hello,
When using the ‘8va' sign above a couple of measures which are extending to some measures into the next staff, I use the method described on page 32 (Change length).
To move the right hand anchor into the next staff I use ‘Shift+Right’.
Because at the start of the next staff the ‘8va’ text appeared, I removed that by unselecting the ‘text’ button in the ‘continue’ part of the ‘Line Properties’ (the box then grayed out).
So far so good. But after saving and reopening the file, the ‘8va’ text keeps coming back
at the start of the new staff.
Is there a possibility to avoid that or am I doing something wrong?
Joe.