Gorm

I have compiled all the GNUstep environment + ProjectCenter and Gorm.
I was trying to build a simple application by following a
video-tutorial.

But in Gorm I cannot drag-and-drop widgets from the palette to the
application window.
It simply doesn't work. As I drop the widget it returns to its home in
the palette window.

Is there anyone who can explain me why and how to make it work?

Thank you