2087167 - Delay for control+tab switcher UI is calculated from when control is pressed, not when the shortcut is completed

Status: NEW

(Firefox :: Tabbed Browser, defect)

Description

[Emily McDonough [:alaskanemily]]

This is a problem if, like me, you press control and then search for the shortcut key.

If you just press control, wait a bit, and then press tab, then the moment you press tab the switcher UI appears. This seems like surprising behavior.

Comment 1

[Stephen Thompson [:sthompson]]

It looks to me like the code only starts the 200ms timer once the full shortcut (Ctrl+Tab by default) has been pressed https://searchfox.org/firefox-main/rev/b0625683b9b8cd108f6b3fa9eedbcd4aa0066d6e/browser/components/tabbrowser/content/browser-ctrlTab.js#589 Testing it out manually, my experience suggests that it shows up 200ms after hitting Tab even if I held Ctrl for a while beforehand. I wonder if 200ms is just too low of a value and bug 2087115 would address this?

Comment 2

[Emily McDonough [:alaskanemily]]

I can record a video if necessary, but it really looks like it's based on the first keypress (the control). If I hold control, wait, then just tap tab for the tiniest moment, the switcher pops up. If I try doing the same with both buttons, it doesn't.

I'm on Linux with X11 if that matters, and testing on OS X Tahoe looks the same to me. I wonder if it's some kind of key preprocessing before it even gets to that point?

Comment 3

[Dão Gottwald [:dao]]

Hmm, I'm on Ubuntu / Wayland and can't reproduce. I think Stephen's reading of the linked code is correct, and certainly what he describes was the intention when I originally wrote this. The only two calls to _openPanel are from the timer in open (invoked when the full shortcut is pressed) and from advanceFocus (when pressing the full shortcut a second time).

Comment 4

[Jeremy Swinarton]

Hi Emily,

Thanks for the report. I tried reproducing this as well, on Ubuntu / Wayland and MacOS, and I'm also not able to reproduce. You said you could repro on two OS's — are those on the same computer? Are you able to reproduce on more than one physical machine? Do you have any add-ons installed, and if so, does disabling them change the behaviour?

It might be difficult to understand the key timing from a video, but if you think it would help, please feel free to post and we will take a look.