Fixed horizontal scrolling with two-finger gesture

[grantwinney]

Test plan

ecd391c

---

Issue:
When a particular webpage I'm using is wider than the screen and requires horizontal scrolling (such as a Trello "board"), Brave treats a two finger swipe as a horizontal scroll AND as a page navigation gesture.

Actual result:
When I two-finger swipe a wide page, it horizontally scrolls the page a bit, but then navigates back to the previous page.

Expected result:
I'd expect it to eat the page navigation feature unless I'm:

• already scrolled to the left-most side of a wide page, then treat it as a page "back" navigation
• already scrolled to the right-most side of a wide page, then treat it as a page "forward" navigation

Environment:
Mac OSX 10.11.6
Brave 0.13.1, SHA 9dd06f9

Any related issues:
None that I found, although someone commented similarly in another issue.

[cndouglas]

+1 from me. Example: https://github.com/brave/browser-laptop/projects/1, scroll horizontally on the cards list.

This is a regression of #2548 (Horizontal scroll with two-finger conflicts with swipe back/forward).

[bgergen]

Glad to see this is a known issue. Makes it super frustrating to try to scroll horizontally to read code snippets or PRs on Github.

[cndouglas]

We've gotten a few +1's for this problem at #5907.

Can we set a milestone for this? I agree with the others that it's really annoying.

[ttfkam]

I would amend the behavior to disallow navigation altogether or at least only on clear gestures. When a page loads, it's not always clear that the page can scroll horizontally. Testing this only to navigate away from the page is non-optimal. In addition, it is common to try to scroll at least once after you've reached the beginning or ending of a view, especially on a large page. The intent is to reach the beginning or end, not leave the page.

Much better to switch this to a three-finger horizontal gesture, at least on Mac. The gesture is not already overloaded/not assigned to anything. It would make the navigation intent clear while leaving scrolling fully functional.

[cndouglas]

@ttfkam Right now, the main problem with the swipe gesture (besides the horizontal scrolling mess) is that it does not respect the system preferences (issue #3299). Ultimately, I think that imitating Safari's behavior should solve most of the problems you described.

Edit: Fixed the issue number.

[cndouglas]

Tagging as a serious macOS usability issue. Please re-prioritize if needed.