I can't drag sash

[Borneq]

I attach two project. In first is OK - I can drag sashes. But second has two buttons and sash between its. Mouse cursor over sash not changed and can't move sash. Why? how move sash?
This examples are from book.

[Borneq]

My error.
instead
sashData.bottom = new FormAttachment(0, 0);
should be
sashData.bottom = new FormAttachment(100, 0);