Close split screen bottom half by dragging to bottom

In the sample project provided with an Actipro install for the SyntaxEditor component, you can see this issue. Basically, when you split the screen vertically (so there are two editors on top of one another), you can close the top editor by dragging its bar to the top, but you cannot close the bottom editor by dragging its bar to the bottom. You should be able to close the bottom editor in that manner.

Thanks!