Option-mouse gestures don't teleport

[cstacy]

Bug report

What you were trying to do (and why)

Zoom the remote screen with opt-scroll.
I want to independently zoom each screen.

What happened (include any debug output)

H1 as server: Nothing Happens.
A hollow voice says PLUGH but that may have been the coffee.

H2 as server:
Both screens scroll !
Which would almost be good enough except:
(a) can't then simultaneously see desired screen content
(b) screens are different size so it's too weird and erratic
(c) I really want H1 to be the server (controller/owner)
(d) lag

What you expected to happen

Current (only) screen (machine) zoom, other machine no effect.

Step-by-step reproduction instructions

Launch teleport on H1 and H2.
(does the order matter? I am using H1's devices.)
Move cursor from H1 (input devices owner) to H2.
opt-scroll in and out

Now do it the other way with H2 owning the trackpad and kbd.

Note #1: All basic keyboard and mouse inputs seem to be working just fine over teleport either way! YAY and HANK YOU! (And of course, real hardware is all doing the right thing on both and no interference from teleport.)

Note #2: Tried toggling Sync lock (whatever that means) to no effect. For the debug scenario it is un-checked on both machines.

Environment information

H1 / H2

• Device: 2014 mini / 2009 mini
• macOS version: 11.4 / 10.11.6
• Teleport version: 1.3.3 (homebrew)

Prefer H1 to be the server.
Magic Trackpad.

[cstacy]

OFFS I mean "Option" key of course. sorry!

[marcpbailey]

Intriguing @cstacy and well spotted. I thought I was going crazy until I read this and realised it wasn't 'just me'.

Actually the title of this might need to be "Modifier keys don't teleport properly with mouse wheel scroll gesture".
I tested with Teleport 1.3.5 on Monterey 12.3 with a Mac Book Air M1 and an iMac 27 late 2013 (with OCLP 0.4.3). Makes no difference which architecture is the master.
Tried a Magic Mouse (first version, with replaceable batteries), a Logitech MX2 mouse and the M1 Trackpad

Horizontal scrolling

The simplest and least configurable of these is native shift-scrollwheel, which scrolls horizontally in default apps like Finder and Preview windows. I found that teleporting results in:

• No MX2 horizontal scrolling on slave (incorrect behaviour)
• Can't test trackpad or Magic Mouse because they natively scroll horizontally (ie correct behaviour)

Accessibility Zooming

Control, option and command scrollwheel modifier keys are configurable for and simple to test with screen Zoom (Accessibility prefpane -> "Use scroll gesture with modifier keys to zoom").

I found that assigning the same modifier (doesn't matter which one as long as they are the same) on both master and slave results in the following behaviour when teleported to the slave:

• Zoom on master (not a typo), no event on slave when using a Logitech MX2
• Zoom on both (not a typo) master and slave when using a Trackpad
• Zoom on both (not a typo) master and slave when using a Magic Mouse
  That is, no case of correct behaviour.

Assigning a different modifier (doesn't matter which ones as long as they are different) on both master and slave results in the following behaviour when teleported to the slave:

• Zoom on master (not a typo), no event on slave when using a Logitech MX2 and the modifier key from the master
• Zoom on slave when using a Logitech MX2 and the modifier key from the slave (ie correct behaviour)
• Zoom on both (not a typo) master and slave when using a Trackpad and the modifier key from the master
• Zoom on slave when using a Trackpad and the modifier key from the slave (ie correct behaviour)
• Zoom on both (not a typo) master and slave when using a Magic Mouse and the modifier key from the master
• Zoom on slave when using a Magic Mouse and the modifier key from the slave (ie correct behaviour)
  That is, mostly incorrect behaviour.

Additional data points:

• All modifier key states correctly teleport for other events like keydown, mousedown, and drag. It seems to be a scrollwheel event specific thing.
• The Logitech MX2 was tested both with and without the proprietary Logi Options daemon enabled; made no difference.
• Intriguingly a Logitech MX2 mouse has a second scroll wheel and events it generates do teleport provided you have Logi Options daemon enabled on both. There's nothing I know of that uses or can test modifiers with the second scrollwheel. This would tend to rule out Logitech driver specific issues and point towards Teleport modifier key handling IMHO.
• Teleport currently runs rings around Universal Control since it does not transmit third party device extra buttons or events whatsoever at the moment. The problem may be Logi Options in that case, to be fair.

Speculation:

I think we can conclude when teleporting that:

• Scrollwheel shift key modifier is broken.
• The master machine Assistive zoom preempts teleport events. That is if you use the modifier key configured on the master, the master will always zoom, regardless of input device, even when teleported. This is broken.
• Slave machine Assistive zoom only works when there is a different, or no, modifier key set on the master. This is broken.
• Both machines zoom when you use the same modifier key and an Apple Magic Mouse or Trackpad. This is broken.

Workaround

However, it's not a huge thing to live with this given that you can set a different modifier key to workaround the zoom issue, and since most people probably have Apple pointing devices, they won't encounter the horizontal scrolling. Me, I'm an MX2 user so both issues are irritating, but not dealbreakers.

Worth adding to the backlog I suspect @johndbritton.

I really feel like these modifier key scroll wheel gestures worked consistently some time in the past; no Delorian+flux capacitor on hand to go back and test this unfortunately.