Logitech horizontal scroll wheel, strange behavior in TortoiseMerge

[Brian]

When scrolling with the horizontal thumb wheel on an MX Master 3, the scroll bar moves but the window does not refresh, with several exceptions. This first exception is related to the second: The first attempt to wheel-scroll horizontally in either pane will succeed e.g. 4 text characters or so. and there is no window refresh after this.

A strange behavior is noticed in dark mode: The scroll bars are both dark on startup. After scrolling horizontally with the wheel, the bottom scroll bar of the active window turns light and responds to wheel movement, but the text in the merge window(s) does not move left or right. If I manually click-drag the horizontal scrollbar, the window scrolls left-to-right normally and the color scheme of the scrollbar returns to dark. After this, wheel scrolling changes the color (back to a light scheme) and location of the scrollbar, but the window does not move left or right---not even the aforementioned 4 characters at the beginning of the horizontal scroll.

The second exception:

I can scroll the left pane 4 characters, then scroll the right pane 4 characters, then scroll the left pane 4 characters, and keep scrolling back-and-forth.

A third exception!

Sometimes unified view allows me to freely scroll, especially if Merge is started in unified view. Then, after switching back to split view, sometimes (but less often, it seems) I can scroll freely in one pane only. Trying to scroll in the other split pane breaks things again.

The last bit of confusion: When the scroll bar is light and not changing the main display, it moves significantly: There are only four increments between the left and right side of the scrollbar with 117 characters beyond the window border. (A split pane on my monitor is 163 columns wide.) When the scrollbar is working, every character may be scrolled individually. That is to say, 100+ increments (and one may even scroll beyond the end of the scrollbar so only one character is visible in the window).

This issue occurs regardless of "Dark Mode" selection and with all attempted combinations of view bars and options. It doesn't matter which settings are configured in Logitech Options. Remapping buttons to horizontal scroll has the same reported behavior.

A potentially related oddity: CTRL+Vertical Scroll does nothing. CTRL+Horizontal Scroll will vertical scroll.

Win10 Pro x64, build 28885 (1.14.0), didn't test nightly and didn't see a changelog entry.

Thanks for your great tool and support of free, open-source software!

[As a last note, the behavior gets even stranger in IDiff. Other Tortoise utilities with single or multiple horizontal scrollbars do not seem to be affected.]

[Stefan]

unfortunately, there's nothing we can do about that.

See here why: https://www.pretentiousname.com/setpoint_hwheel/index.html

and my previous attempts on this problem: https://gitlab.com/tortoisegit/tortoisegit/-/issues/3550

[Brian]

Thanks for the quick response. This looks like quite a hassle, and I don't imagine either of these giant companies is willing to change a decade-old design decision.

If there were a scroll left and scroll right keyboard shortcut, the wheel could be configured for just TortoiseMerge to send the keyboard shortcut. It's a terrible workaround, but it would work.

Fortunately, horizontal scrolling is something I barely use, so I usually wouldn't mention it. My post only grew to its epic length from being thorough about reporting and then discovering another nuance to this bug.

Cheers