What is this plus sign in a text box in draw.io app, and how do I get rid of it?

Question

I just got a draw.io file (from https://app.diagrams.net/ or the app, draw.io-13.6.2-windows-installer.exe which can be downloaded from the same page), which I try to edit in the app, and i've noticed this in a text box:

What is that + in the box on the left? I cannot delete it as a character; if I click it, it toggles to - (so apparently it is meant to expand something - but it is pointless here, there is just one word in the box).

So what is this + for - and how do I get rid of it?

(just noticed there is no tag for draw.io or diagrams.net here - if there is a more appropriate forum for this, please let me know)

Answer 1

Ok, figured it out - if you select that text box, right-click it and choose Edit Style, you get this box:

All you have to do is delete the container=1; part, click Apply - and the + sign will disappear.