Arrow with little black box keeps moving my columns

[Guest]

Hi All,

PROBLEM:

I inherited a lot of InDesign documents and cant figure out why the margins keep moving.  When I move my cursor over the magenta column line (vertical line), the arrow turns black and has a little black box to the bottom right of the arrow.  Sometimes all I want to do is move the text, but the columns move instead.

What option do I have to turn off or on to keep my margins from moving?  I don't want to adjust individual margins.

Thank you,

Chris

[Mike Witherell · Accepted solution]

View > Grids n Guides > Lock Column Guides