I’ve looked at everything in the editor, and yet I cannot find any options to change the look of the aforementioned UI elements. The only parameters under Theme change the font (and, in case of the ScrollContainer, the panel, but not the scrollbar). How do I customize the looks of those UI elements?
Some UI elements are consists of other multiple Control Nodes, or derivative of them.
For ConfirmationDialog, you can check the type AcceptDialog in your theme for some elements. But for example, the buttons there are from the Button type. So you have to change the Button style also.
For ScrollContainer, I think you need to check the type VScrollBar to change the scrollbar style.
The ScrollBar is fine, but I’m still experiencing some problems with the AcceptDialog window. I can’t seem to find where to change the color of the text inside the window (to make it different from the title of the window), and how to change the cross button (color and position?). Also there are square borders that I don’t know how to get rid of. Would be happy if someone could help!
If you want to change the position of the buttons, I think it’s easier to just create your own dialog box with Panel Container, Label and Buttons. You’d achieve the same thing with more flexibility.