Frozen-locked Tab Stops in Graffiti and RED

A very peculiar problem has cropped up at some point after installing Graffiti on my system: all custom tab stops in all text windows are completely frozen. I also cannot set new tab stops, or interact in any way with the tab stop "type" icon on the ruler intersection.

In the past, I had no problem with any of this when using RED. But now both RED and Graffiti are exhibiting exactly the same problem.

This is true whether I use the apps in stand alone mode, or as plug ins to Sony Vegas.

I am running the latest version of both apps, and my video drivers are the latest version. I've also submitted this question to the Boris Tech people (twice), and have yet to receive any answers.

Any suggestions?