I have the same problem (SMF 2.0, ezportal 0.51). I cannot get rid of the pesky collapse buttons in the upper left corner, despite the fact that the columns are set to be non-collapsible.
UPDATE: I went into the database with phpMyAdmin. in the smf_ezp_columns table there is a field called "can_collapse" and the values for Left and Right are set to 1. This, despite the fact that when I try to modify those columns, the checkbox is empty. And, when I save the columns with the empty box, the 1 values persist.
So, I had to change these values to 0 by hand to make the callapse images go away.