In an SDI application...
Clicking in the dropdown list causes the owning form to lose focus. Thus, when you pick an item, the titlebar flickers (ie. deactivates and activates). To more easily see what I'm talking about, simply use an empty C1Combo, click the button to drop the list, and then click in the list.
In an MDI application...
Same thing, except worse, as not only does the owning, child form lose focus, but also the MDI Container. In other words, there are 2 titlebars flickering (ie. deactivating and activating).
Vince