I've googled and googled and found no solid answers on how to do this.
I basically want to provide a my own drop down selector control for the DropDown control. Failing that being possible i'll happily write my own usercontrol for this, that however led me on a complicated path for how to do your own popup functionality at all in .net with C#. The use-case is a dropdown that allows you to select an image from a pallette of images rather than just a list of file/image names. I also want to be able to filter the contents of the dropdown listview/image pallette differently to the standard way that the C# DropDown does it.
I have found the .net Popup class, it works but you're unable to assign a UserControl to the child field and so i won't be able to popup my more complicated palette view.
I have also seen solutions where a ToolStripDropDown was used, but that didn't allow me filter the contents of the view by typing in the textbox above it.
The solution i have at the moment is to fake it with a separate form but i get all sorts of issues to do with managing when it should be shown and hidden based on the focus states of the control that spawned it etc. Also, if i spawn it and then move the main application window it then ofcourse gets left behind.