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Method 5: Determine whether it is application specific
With newer “high-resolution” mouse devices, some applications may not correctly interpret partial scrolling messages. When low resolution wheels scroll up and down, the mouse driver sends a scroll magnitude of 120 for each tick of the wheel up and 120 for each tick down. According to the official documentation, a scrolling value of 120 (or -120) indicates one line of scrolling. If the application receives less than a full line, it should either scroll part of a line (which is what Microsoft Word and some other applications do) or if that’s not possible, save up the value until a total of 120 is reached (which is what Notepad does). Most current Microsoft mouse devices are designed to give a smoother scroll experience, so the wheels are higher resolution and send four times as many scroll events, but at one-quarter of the magnitude. So instead of 120, they send 30 (or instead of -120 when scrolling back, they send -30). This should result in scrolling at the same speed, just more smoothly.

Some applications may not handle this correctly.

For example, they may ignore partial scroll events, or they may interpret a partial (30) event as a full line (120). There have been instances of some applications that actually combine both of these incorrect behaviors. For example, some applications may ignore the positive partial events and treat negative partial events as a full line, which would result in slow scrolling forward and fast scrolling backward.