I recently upgraded to Ubuntu 14.04, and at the same time started using xfce. My laptop is an lenovo SL-500, but I use an external usb keyboard with more or less the same keyboard layout (lenovo sk-8845, picture at ).
I used to be able to easily move the mouse a single pixel at a time using the trackpoint of either device. I still can with the trackpoint on the laptop, but not with the external keyboard. It seems to always move (jump) 5-10 pixels, regardless how little I touch it. This is driving me nuts, since I can't do any fine-grained motion (e.g. getting the pointer within the small area allowing me to resize a window, or above a scroll bar to let me drag it). I tried tweaking both acceleration and sensitivity in Settings->Mouse and Touchpad, but regardless of the settings, the pointer still seems to move this minimum distance.
41 Answer
See TrackPoint hard to control after Debian update and the linked Debian bug #682413 "USB TrackPoint keyboards unusable since synaptics-usb was included". It appears a patch to the 3.2 kernel changed the behaviour of the Synaptics USB driver so that it now reports raw values instead of normalised values. The fix patches from Andrew Deason mentioned in that bug report have not been applied upstream (see tip:drivers/input/mouse/synaptics_usb.c). If these patches do fix the issue for you, then please chase the issue up on the linux-input mailing list so that it gets fixed upstream. You could also contact the author of Synaptics-usb.
