To debug this I tried to hack with the console giving it: 

monitorEvents(document.body, 'mouse')

But the event was not appearing. So I gave it:

monitorEvents(document.body, 'keydown')

and scrolling horizontally, it fired a keyboard events instead of a mouse one.

Hi cerquone@, I can't reproduce the problem. For example, I went to http://bokan.ca/textbox.html, placed the cursor in one of input fields and scrolled horizontally (two finger scroll) on my touchpad. The text scrolls horizontally without moving the cursor. Similarly when I selected a region of text and no keyboard events are fired at all.

Perhaps your mouse driver is simulating the key events? What does Firefox or Edge/IE do?

We all thought that it was caused by a driver "feature", but actually there is absolutely no option such that on the "dell touchpad" panel.
Anyway I visited that page with IE and Edge, I scrolled horizontally but absolutely nothing happened (the cursor DIDN'T move nor the text)

cerquone@; can you help us diagnose this because I don't have the same hardware as you.

1) Are you able to attach a chrome://tracing log?
2) Are you able to dump the events via Spy++?

The chrome tracing log is attached with this message. (I selected "web developer" before recording it)
I don't know what spy is, let me know if it's necessary!

Deleted: trace_touchpad-problem.json.gz 1.5 MB

trace_touchpad-problem.json.gz 1.5 MB Download

Thank you for providing more feedback. Adding requester "dtapuska@chromium.org" for another review and adding "Needs-Review" label for tracking.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

For Spy++ if you don't know; then likely you don't have the software. It is part of Microsoft Visual Studio.

Please provide a trace with input latency selected. Although I'm not sure it will reveal anything.

What specific Dell laptop do you have?

cerquone@, a "web developer" trace doesn't give us enough details to diagnose. Could you attach a new trace with "Manual" settings and then select all categories in the list on the left and none from the right.

Unfortunately there isn't any action we can take here and we have been waiting for feedback. Closing the issue for now. If the reporter can provide more information as to the hardware, traces we might be able to analyze it further.