IPickTreeItem and setWidth("*")

v9.1p_2014-07-06/Pro Deployment (built 2014-07-06)

Is there any way to have the IPickTreeItem fill the space allocated to it's column using setWidth("*")?
I seem to be able to setWidth(some_int), but if I use "*", it does nothing.

FF 24.6.0 ESR.

Thanks