I have tried both keyboard strokes, as well as using only the mouse. In general, both Security Assist and Data Assist both need a double-click (tab key doesn't work) to get the changes to take.
I JUST purchased Security Assist, and I'm using the following WA components on my site:
SA - 1.1.8
DA - 2.0.6
eCart - 4.5.2
Dreamweaver CS4 (version 10.0, build 4117)
Mac OSX 10.5.8
Proc - 2.4 GHz
Mem - 4GB 667 MHz DDR2 SDRAM
HDD - 140 GB, 19 GB free