Hi,
THX Barry for pointing to mouse driver:
Here is what my tests found:
1. Every Mouse Hardware have scroll speed and Report Rate, some defaults My defaults are 500hz and Scroll Speed 1 and exactly like on
your Video single scroll point tells MM to scroll 3 lines of height 24px (my font is 100% and line is 18px) which result in scrolling 4 lines visually. Keyboard navigation tells MM to scroll line height eg. 18px so there is no effect.
2. Changing Scroll Speed to three then one scroll point scrolls exactly 12 lines because repeat rate on Scroll point is multiplied by 3
3. Increasing Report Rate lowers LAG in Scroll event so it is harder to scroll only 1 point, usually I get 2 every few points and I suspect on lower quality scroll sensor
4. All test are done in RAW/Direct Input Mouse reading and when I tell Windows to send/handle mouse scroll events (eg. default value) things are becoming mess where I can't easily find which is head and which is tail. To be honest I have not planned to write a study about mouse scroll speeds, behavior, settings, sensors, hardware, build quality, software, driver, Windows.
The solution for MM would be to handle RAW Mouse Data, but I personally think that it would 1000% create more issues than it would fix.
My Mouse Initial Test settings and how I changed them:
EDIT: Forgot to mention the mouse used in testing is
RedDragon M908 Impact