How can I adjust column widths in Apache OpenOffice Writer?

I have an Open Document Text (.odt) file in A4 landscape mode. One section of text is four columns (not a table, but textual columns). I want the first and last columns to be narrower, and the central two to be wider.

If I go to Format → columns, and tick the AutoWidth box, the columns come out as 2.45" each, with a 0.10" gap between them. If I adjust the first column down to 1.45", the second immediately goes up to 3.45", which is okay. However, if I then adjust the last down to 1.45", the first goes back up to 2.45". The numbers keep jumping around.

I did eventually manage to get this to work, but I’m not entirely sure how, and if I wanted to do it again I’d be no wiser on how to go about it. Is there a way to stop OpenOffice being so smart and automatically adjusting column width? I’d like to take control and adjust all the widths myself.