Editing a Pick List, but no space available

Editing a Pick List, but no space available

I'm a single user, using the free version. 

Apparently, I've reached my limit in my ability to add new choices to several of my drop down Pick Lists.

When this happens, a dialogue box appears, I check "OK" and I can't make any more additions to the Pick List.

This process also locks up the program & my PC.

I need to close the program, wait, and then restart the program. 

First, how can I solve this issue?

Second, will upgrading to another (paid) version solve this issue?

Thank you! 

Ken