Is there a configuration or app that will enable Sticky-keys like functionality for a pointer button under X11? (On Ubuntu 9.10, FWIW.) To be clear, I'd like a single tap (down/up events) to be treated as a down event, and a following tap to be treated as an up event.
Context: I have a trackball with a fourth button that I've mapped to act as horizontal/vertical scroll. This works great. It'd be even better if I didn't have to hold the button down when scrolling.
