Key combination alt + number key are not registered/passed to browser

[kafji]

Bug description
Key combination alt + number key (i.e. 1, 2, 3, ..., 0) are not registered/passed to browser with Vimium installed. On Linux those key combination are used to switch to a tab based on its position, i.e. alt+1 will switch to the first tab.

Reproduce steps
Steps to reproduce the behavior:

1. Install Vimium from AMO or load from fbddc22
2. Open multiple tab any URL is fine
3. Press the key combination to switch tab

Browser and Vimium version
Browser: Firefox 77.0b8
OS: Linux 5.4.0-31-generic, Kubuntu 20.04

This issue does not present on Windows 10 and MacOS as they are using different key combination to switch tab, ctrl+number and cmd+number respectively.

[kmARC]

Ha, I have the same issue since a week or so. @kafji did you find any workaround?

[gdh1995]

Could you do a simple test to find what Vimium got?

• open https://gdh1995.cn/vimium-c/keyboard-test.html
• click Vimium's icon and save options to make Vimium disabled on the page
• reload the page, and enable "Prevent all keyboard events"
• then press Alt+1, Alt+2 to see what it will log.

[kafji]

@kmARC

did you find any workaround?

No. :(

@gdh1995

On Firefox 82.0 w/ Vimium disabled:

 	Event 	Code 	Key 	Modifiers 	KeyCode (legacy)
1 	keydown 	Digit1 	1 		49
2 	keyup 	Digit1 	1 		49
3 	keydown 	Digit2 	2 		50
4 	keyup 	Digit2 	2 		50
5 	keydown 	Digit3 	3 		51
6 	keyup 	Digit3 	3 		51

On Firefox 82.0 w/ Vimium enabled & delayed keystrokes:

 	Event 	Code 	Key 	Modifiers 	KeyCode (legacy)

Keystrokes are delayed less than 2 seconds.

On Firefox 82.0 w/ Vimium enabled & rapid non-distinct keystrokes:

 	Event 	Code 	Key 	Modifiers 	KeyCode (legacy)

On Firefox 82.0 w/ Vimium enabled & rapid distinct keystrokes:

 	Event 	Code 	Key 	Modifiers 	KeyCode (legacy)
1 	keydown 	OSLeft 	OS 	Alt 	91
2 	keyup 	Digit2 	2 		50
3 	keyup 	Digit1 	1 		49
4 	keyup 	OSLeft 	OS 	Alt 	91
5 	keyup 	Digit3 	3 		51
6 	keyup 	Digit1 	1 		49
7 	keyup 	Digit2 	2 		50
8 	keyup 	Digit3 	3 		51
9 	keyup 	Digit2 	2 		50
10 	keyup 	Digit1 	1 		49

[gdh1995]

Well, this is because Firefox has a bug of reporting wrong statuses of the Alt key. In other words, Firefox lacks a feature of getting correct Alt statuses.

This is a "common" bug - on Linux-like systems, Firefox has quite a few bugs about handling keyboard events.

It seems for Vimium there's no means to work around it.