For example, I have a frame and itself is not scrollable. It also has a child frame which is scrollable. How can I make that child frame to scroll and get its content?

I tried making frame to be group, but then find that some styling can be lost, like background color and border. I also found that making a frame to be a group could sometimes break the layout as its width and height is changed.

For now, I am thinking if I can make screenshots in preview, but it seems the Plugin API is not providing that feature.