Setting on Full Scan can't be saved in NIS 2012

Open Settings - Computer Scan, the default value in Full Scan dropdown is CLOSED. When I change it to Monthly or Weekly, and click APPLY button, but this button doesn't gray out. Then click OK to close this window and open it again, the value still is CLOSED.

 

WIN 7 ULTRA x64 - NIS 2012 19.1.0.28