I am looking for composite widget example. Does anyone know where to find one?

What I am looking forward to make is something like:

...............................................
|            ........................... .....|
| Parameter: |                         | | X ||
|            Y........................./ Y...||
|            ,-------------------------b      |
| Type:      |                         |      |
|            Y.........................P      |
|            ...........................      |
| Default:   |                         |      |
|            `-------------------------'      |
'`'''''''''''''''''''''''''''''''''''''''''''''

I intend to have a list of these that is growing/shrinking dynamically. I will use it in my GUI code generator for functions/methods.