Sorting by columns header in table forms

On Servoy 3.5.10 (not yet confirmed on Servoy4/5) when I define a table form I’ve the problem sorting on column header it is not consistently working.

  1. If the table form is defined as new form it is correctly working.

  2. If the table form is converted from a list form it is not working. IF I rebuild the same form from scratch it works!

What am I missing here?
There are form/tables/fields attributes inhibiting column sorting to work?

Can anyone point me in the right direction here or it is simply a bug?

Tnks for any reply!
Gianni

something similar happens if you use a header (not title header) on the form, maybe is that the problem?

Andres