Unlike the pan and crop in Vegas 6, in my version 9.0a, I can slide the frame horizontally, I can move it vertically, but not sideways. Is this a known bug? Is there a workaround?

Sounds like you've turned on the option to limit the direction. There's three options: free flow (what you're wanting), horizontal only, and vertical only. To change this, you need to click on the bottom button on the left side. It toggles through these three options.

Also, I see you are on VP9a. In Pan/Crop there was an unfortunate Rotation error around 45 degrees, which made the picture go out of focus and produce star type FXs, but that has now been rectified in VP9b. SO you might want to consider updating to VP9b while you are about it? Maybe wait till you have finished your present project?

Grazie

I'm curious why anyone would want to self impose that restriction on a project? Why would want to disable fully or partially the ability to slide an image around?

Why would want to disable fully or partially the ability to slide an image around? Oh, simply to keep that image on either the horiz OR vert while manipulating the image's position. It's kinda like "locking" the Pan or Tilt of a tripod? After all, this tool, as well as allowing Cropping is a Panning AND Zooming-in/out tool.

Here are some I used recently. Stills that need to be panned across. I've used it to ensure I keep the horiz datum without a hint of vertical movement. Vertical movement over a document or list. I recently used this vert lock for tilting down a church steeple.

Grazie