Do you have a program called "WizMouse" installed? This has been known to cause the issue.
Another cause has been the config.pro option "set_trail_single_step" to a value of "yes". This was reported as affecting Creo 3.0 but it may have also affected some Creo 2.0 datecodes.
Before I hadn't installed any "WizMouse" software and "set_trail_single_step" was set to "no" by default. Still have same issue. Scrolling works fine in another software. Despite I switched the things too, installed "WizMouse" and checked it using "set_trail_single_step" by "no" and "yes", Before and after are same situation.