I think it depends on who you are building it for. If the client is stupid, and thinks .Net is new and hence better, then create it in .Net. However, I think un-managed apps will have problems with it. (Not sure). And I am not sure, even if it is possible to support the things you need. .Net is new, and you won't find (m)any experts in it. If on the other hand, you are serious about creating the control, that is easy to use, easy to modify, can be controlled to the finest of details, is real-fast, then go for Un-managed. And you can get help from the Gurus if you ever get stuck. 1- It can contain web-browsers, if you need them. 2- It can contain buttons, list boxes, etc. 3- Can adjust its position, size. 4- Can support drag-drop. (Not sure how .Net apps will behave to that). this is this.