hi,
10X for the "CanParent" tip, i solved it through overriding the
"OnControlAdded" method. which is better way to do it ?

and regarding my base problem, i kind of got to the next phase - i now have
a usercontrol of type "A" who can hold  lots of usercontrols of type "B". if
i drag the "A" and then drag the "B" into "A" i CAN add other controls to
"B". that was my initial meaning !!!
BUT, while this situation is ok, i rather want "A" to have a collection
property of "B"s (like tabcontrol with tabpages etc) with all "B"'s
properties.
this cause me 2 problems:  
1) i understood i need a collection class and an item class and lots of
other stuff. is there a good article/code example anywhere about it ? couldnt
find any that is really thorough... (Joey - i already saw the article you
attached, 10X a lot but this example do not really take care all the aspects
i need, although when read it, i started to understand what is waiting for
me....:))
2) i kind of succeeded in doing something like a collection (simple property
who makes on design time "B" and add it to "A") but then i couldnt see it on
the  "InitializeComponent" methode of the main form, in other words - i
couldnt add to "B" other controls...  
i figure that if problem 1 will be solved i wont be bothered by 2 but if
there's something to do on the meantime... :)

10X,

I have a similar user control designer issue.  You mentioned ' I was able to
replicate the .NET TabControl with buttons to click on and panels as detail
where user can drag controls into.'  Is there any way you can post that?  I
am trying to develop a custom tab control that unfortunately extending the
existing tab control won't do.