Possible bug: when changing the translate plane on the transform handle, it fails to update the change until the view is changed. I'm accessing these with hotkeys so I'd like it to change immediately without moving the view, otherwise the workflow is slowed down.
Build 9.5.178, winxp 64

on an additional note, I'd like to share a request for enhancement for the transform handle. Houdini is the only major 3d package I know of where you need a menu or hotkeys to change the “translate plane”. Max has a really big gizmo that makes it easy to grab the xy, yz, or xz plane on the transform handle. In XSI, grabbing in the middle will move it in screen space, and when the mouse hovers around, the “transform plane” will automatically change logically based on the mouse position. It makes for really fast transforming workflow (scaling as well).

I'd like to see something like this (or even better!) for Houdini!

A really cool feature in Maya (though I've never been a big maya user), especially for animators, is the ability to click the translate or rotate handle, then hold down a hotkey, and click-drag the mouse anywhere in the viewport, which will act as if the handle was pulled. This allows for repeated movements without having to go back and keep clicking the thin transform handle.

While we're at it, it would also be nice to have a hotkey to be able to snap the rotate handle to desired increments. I can't tell you how many times I've used the angle snapping in 3ds max to quickly move from 0 to 90 degrees, and have it snap by adjusting the rotation in 5 degree increments.

An alternative to implementing all these enhancements would be to open up hooks to allow us to script our own, or modify, transform handles with python. Thanks guys for making Houdini as awesome as it is, let's open it up so we can do more with the interface!