Yup, you found it. We didn't have time to put together an options dialog before releasing the app, but at least the option is available in the config file.
For others who are looking, the per-machine configuration is here:
%ProgramFiles%\Microsoft Research\Cliplets\Cliplets.exe.config
The per-user configuration is in a location similar to the following:
%LocalAppData%\Microsoft_Corporation\Cliplets.exe_Url_2okoj0b14d0g5h5iorwmxzz2nnwrc4ia\1.1.1.0\user.config
Eric Stollnitz, Interactive Visual Media Group, Microsoft Research