Calculated pens

I’m using version 7.6.6

I’ve tried several times to create a calculated pen for Ave or Moving Ave of one of my db pens. once I click OK on the Easy Chart setup, the designer closes. Is this a known bug, or am I trying to use this feature incorrectly?
All I want is to do line smoothing on some of my db pens.

You can try uninstalling the designer and restarting-- note: this gets rid of whatever other cached sessions and icons you might have as well.

javaws.exe -uninstall 

What version of Java are you currently running? Also when this happens do you see any errors in the Gateway Console in regards to the designer?