Various question in one topic:

I have a table with a data field of type "JoomlaUser" within it.
I have a front-end item and a front-end collection layout on that table that theorically display this field.
I expect a JoomlaUser to make the jointure between my different tables (I don't see other means to do it)

At the time of layout creation:
1st:
I didn't got any layout in the drop-down menu to do this even I am sure the same field exist in my other layout.
(I regenerate project files between both to refresh the project but do not change anything).
2nd
At the time to display this in the browser front-end in the fly item the Joomla User stay void.

Any help to overcome this is welcome...

I have some table with Joomla User as field. Nothing than normal.
A the time to display it in the front-end
The Joomla User Name Username are not displayed in layouts generated by COOK.
Why this ?
I think it's important to understand this.
If I put a form where user properties are editable and I am logged as Super Admin I cannot edit them.
Please someone explain.