width of a textbox (textnode) cannot be edited

Hi,

in some of our (old) files there had been placed text/textnodes by using the method „line break“.
If I have to edit these texts it is not possible to enlarge the textbox and to enter further text within a line.
The ruler in the text editor is fixed.

Is it possible to “unlock” the ruler to enter some more words in a line or to define a different width of the text box (textnode)?

Thanks,
Petra