Hi everyone!

I'm at the developer mode and I'm editing the Invoice form view with Studio in a Odoo 15 environment.

I have created an additional Tab for a record and what I am trying to do is to add fields to this Tab but when I try to do this it only shows the spot where it will be added and nothing happens, I noticed that the only way in which I can add a field is by adding it first to the record and then moving it to the tab, but I don´t think this is normal.

Then I'm trying to add columns and it behaves as the same as with the fields, It shows me the spot where it should be added but nothing happens and if I try to add it to the record and then try to move it to the tab it is not possible.

Finally, I try to add a tab within a tab and is behaves as the same as with columns.

I don´t know if I have to do something first or if this is something not normal.

I'll appreciate your help with this issue, thanks!