Description
Due to a problem in the Quartus® II software versions 10.0 and later, scrolling by using a mouse wheel may not work properly in the Quartus II Text Editor on Windows. This can occur if your mouse wheel is configured to scroll by one screen at a time.
To work around this problem, configure your mouse wheel to scroll by a number of lines at a time instead of by one screen at a time. This setting can be configured by opening the Mouse Properties dialog box from the Windows Control Panel and selecting the Wheel tab.
This problem is scheduled to be fixed in a future version of the Quartus II software.