How are you creating the new rule? When you are in the rules interface are you using the keyboard to make or confirm any selections? If so please try to use only the mouse to confirm your selections to see if it helps.
Also, what is the version of Security Assist that you have installed and what is the DW and OS versions you are working with? I will use this info to check into this further with you, if need be we can open a ticket on this issue to exchange any further details.