PCB design is always done on large monitors (24" 1920x1200 etc) and often 3 of them in a row!
Trying to do it with only 768 vertical pixels is a little crazy
In any case, to fix your current problem just set the taskbar to auto-hide mode.
That will give you some extra room and allow you to click the buttons.
( right click on the taskbar / properties / tick 'auto hide the taskbar' )