I had an issue with the trackpad of the BB that I would like to remind (link).
I had the BB in the pocket and probably some keys + the trackpad was pressed in a sequence that I still do not know.
The issue was that the vertical move of the screen was stopped in some screens: an e-mail, main screen… and I was required to press the “alt” key to move on the screen. There were no physical issue, for instance on the e-mail inbox the move worked perfectly.
What I did to recover the initial configuration was to install an application and uninstall it. The complete reboot made the issue disappear.
Unfortunately for me I still do not know the sequence of keys I have to press to have the issue resolved.