Laying out panels in DrScheme is simple,
Inside your frame you can have multiple panels (or panes), and these can contain other panels. The default behaviour is for panels to share space equally with siblings sharing the same parent.
This can be varied by using the min-width and stretchable-width arguments.
Have a play with the window generated by this code;
note:
# you will have to make the frame bigger by dragging the handle on the bottom right corner
# this example uses the 'framework' collection to add draggable functionality that is useful, and helps you get a better handle on how panels interact. (you can replace panel:horizontal-dragable% with horizontal-panel% for the plain vanilla version)
A GOTCHA: one thing that might be confusing the first time it happens is adding controls like text-fields; if you create a text field with a large initial value, the parent panel will expand, the parents siblings and the frame may also expand in unexpected ways. You can avoid this by creating the text-field% control, with stretchable-width as #t and setting its initial value with the set-value method.