How to remove the extra column while freezing in jxl api?

How to remove the extra column while freezing in jxl api?

Using jxl, I'm trying to do both horizontal and vertical freeze
sheet.getSettings().setVerticalFreeze(7);
sheet.getSettings().setHorizontalFreeze(1);
The horizontal one is fine, but the vertical one adds an extra column
(narrow column). Not only that - if I open up the excel file, unfreeze all
columns, and try to freeze again manually, it adds the extra column again
!! Something gets messed up, while the file is generated.
Any idea how to fix this?
I'm on Mac, and using MS office on mac