Xojo r2 or r3 broke MouseEnter for LSUIElement apps?

I have a Cocoa app (iClip) that runs as a LSUIElement app, i.e. it has no menu bar.

When built with Xojo r1, its window receives MouseEnter, MouseMove and MouseExit events just fine.

But with Xojo r3.3, these events do not arrive any more.

Does anyone know more about this, e.g. a work-around?