Multiple suggestions have been made already as to how to improve upon the control scheme also in terms of consistency. Zooming in on the monitors with the mouse wheel shouldn’t really be a thing. Instead, the mouse wheel could be put to better use for scrolling lists (infopedia).
That being said, if the PDA displays too much text, it just cuts it off instead of giving the option to scroll down. Also scrolling down requires left-clicking without the option to hold down left click for continous scrolling. Of course, the mouse-wheel option for scrolling would solve that as well.