App window resized to screen resolution becomes frameless fullscreen

When resizing a window to the same geometry of screen, the window becomes frameless and fullscreen.

When running this app in a RHEL7, or other linux distro, the window simply starts maximized, as expected.

But in RHEL6, with gnome, it becomes fullscreen and frameless window. 

Attached is a sample app that reproduces the problem.

Thanks!