About Popup Panels

[maxm74]

I've seen that TBCComboBox (maybe others too) use a Popup Panel to show.
What do you think about creating a common class like TBCPopupPanel, so that TBCComboBox derives from it and we can create other components with the Popup style in the future?
The only doubt I have is how to manage a PopupPanel that can be filled by the user at design time because it would occupy its space when in reality it would be hidden, in the case of TBCComboBox the problem does not exist because it is filled at runtime.

Thanks.