@Peter ... I've had this problem forever with Evernote. One of the poster got it right: What is the behavior of the edit window when you click the scroll bar's up/down buttons instead of rolling the mouse wheel? Why is this right? Because let's stop talking about the mouse wheel, the mouse driver, the setpoint app, ad nauseum. If I have the operating system setting for the wheel to give 1 "line", then one wheel roll-notch should equal one click on the scroll bar up/down buttons. So setting that, here is what I measure: Evernote scrolls the text about 2.5 lines for each scrollbar button click. Evernote scrolls the text about 4 lines for each mouse wheel roll-notch, when wheel is set to "1 line" in the control panel. As a comparison, I do the same thing in Notepad, and each of the above yields exactly one line of text. So the problem is the Evernote app, not the operating system or the driver or the device. Basically, whatever you're reading from the operating system, you're scaling it too much when applied to the edit pane. Now, maybe you don't observe what I'm describing, but that's probably because you're observing it on a platform where it does work out to one line. Maybe you're using a Mac. Obviously, I'm using Windows. There's more that the mouse at issue here. There's the drawing API provided by the operating system also. Just saying that you're "taking whatever is handed to you by the operating system" is a cop-out, because at the very least, you could build a workaround into your app's Options where the user could specify the scaling.