Listbox Horizontal scrollbar not visible

I cannot see the column that just got added. The ScrollBar is missing.
I increased the column count on a Listbox, so the column is probably off the screen.
But the Listbox Horizontal scrollbar is not visible, and it is set to true for visible.
I made sure the count changed from 3 to 4. I can probably adjust the width of the columns so I can confirm there is an extra column.
Is there anything else I can do?

Please, read the docuentation:

Extract of the LR:
You are responsible when the user does this, and you need to provide a horizontal scrollbar so that the user can get to the any headers that have been pushed out of view to the right. You enable this mode by making sure every column width is specified in terms of an absolute pixel width, or a percentage width (e.g. “20”, or “35%”). If you use an asterisk or leave a column width blank, you will automatically be using the first mode.

Thanks. I didn’t have them defined, and if I don’t they are dispersed equally.
The next run the four columns were equally dispersed in the visible space.
For some reason on the first run only three were visible, and no scrollbar, and the column count was four.
On the next run, I had this code GrmLstBox.ColumnWidths = "140, 140, 140, 140" and the bar appeared. Weird for the first run.