Dialog box / Sub-application objects

I want to get rid of the icon in the titlebar of the DialogBox object and the Sub-Application object when set to open as a popup. Is there any way to do this? I know you can do it by not checking "System menu" but this also gets rid of the close button, which I want to keep.

if it doesn't hurt you can use the "toolbox" option

I know, but that looks kind of silly. :( I really hope an option can be added to both of the objects to disable/hide the icon.