Either I'm missing something or no one at C1 tested the C1DropDownControl in an MDI application.
1) Using a dropdown in a child form causes the MDI container (ie. main form) to lose focus
2) Create two child forms, the first with a textbox and a dropdown, the second with just a textbox. Run the application, open the first child, and then open the second. Now, switch back to the first child by clicking in the textbox. Next, click the dropdown's button and the click off the dropdown somewhere on the first child. As you will note, the blinking cursor is in the textbox of the decactived second child -- and if you start typing, the text goes into the textbox of the deactivated child form without activating the form.
Both of these need to be fixed.
Vince