One program won't display full screen

[shopic]

I have one program that won"t display full screen? Windows xp, version 2003, service pack 3, I thank you for some help.

 

[mailpup]

And this program is?

 

[shopic]

full screen

the program is zen, national league of poker, it has been full screen for months, today i logged on no full screen, all other programs are full screen. thanks!