Hi, 
 As your testing result shows, it is a member function which can mask what users can enter on Dialog control. The syntax is 
BOOL Edit::SetContentFilter(int nFilter)
The Parameter nFilter could be 
CF_DOUBLE,	//allow unsigned numeric only
CF_INTEGER,	//allow unsigned integer only
CF_SIGNED_DOUBLE,	//allow signed numeric only
CF_SIGNED_INTEGER,	//allow signed integer only
Cecilia
OriginLab Corp.