fields disappearing when grabing them

[André.Bisseret]

Hi,
In a stack, I have groups of fields so that when one is visible the  
others are invisible.
Each field has its "lockText" and "list behavior" properties set to  
true.
The user can edit the visible field by means of buttons (adding or  
deleting a line).
So, the number of lines (the lenght of lines too), can increase or  
decrease ;
When the content is changing, the size of the field is automatically  
adapted (using formattedHeight and formattedWidth).

Consequently, I would like that the user could change at will the  
position of the field in the card.

So I am trying  to use "if command key is down then grab me" in the  
script of each field.

BUT, MY PROBLEM is that, when grabing it, parts of the field   
disappear (and possibly the entire field) as if it was sliding under  
other (invisible) objects !! that, in fact, do not exist there  
(except the invisible other fields of the group)

For a while, I supposed that this was due to the other fields of the  
group (?), so I set all of them to "transparent" (opaque property to  
false). But that does not work.

What am I doing wrong ? could it be a problem of "group boundary" ??
Is there a solution ?

I hope my explanations are not too unclear !

Thanks a lot in advance for any solution or idea to solve this problem

Best regards from Grenoble
André