On-release binding not triggered if was pressed before Rofi launch

[sergei-dyshel]

Version: 1.4.1 (tags/1.4.1)
Configuration - Default

I'm trying to simulate Alt-Tab behavior, as found in common desktop environments (e.g. Windows or Gnome), using Rofi in i3 WM. Alt-tab is supposed to work this way:
As soon I press Alt-Tab, Rofi window appears. While holding Alt, I cycle to next windows with Tab. When I release Alt I switch to currently selected window.

So far binding Alt-Tab (in i3) to this simple command does the job pretty well:

rofi -show window -kb-row-down 'Alt+Tab' -kb-accept-entry '!Alt_L,!Alt+Tab'

There is, however, an annoying issue: if I don't want to cycle at all, e.g. switch to first (currently selected) window, I'm supposed to release Alt-tab immediately after opening Rofi window, which should trigger kb-accept-entry.

But this doesn't happen! For some reason on-release binding is not triggered. I suspect that it happens because when Rofi started, Alt-Tab was already pressed. So it sees the release of Alt although Alt wasn't pressed. Anyway, I tried going through the relevant commit (67b0ce0), but couldn't figure it out.

I'd like to attempt fixing this on my own so any explanations or code hints are welcome!

[sardemff7]

You are hitting a limitation of X11 here.
We get the modifiers status from the X server before the list of keys already down. That means we do not see Alt_L down, but Alt+Alt_L. It should work fine if you bind !Alt+Alt_L to accept-entry.
This is the case on Wayland too, but on X11, we never see the Tab key as down, because the WM (or whatever launches rofi) has grabbed Alt-Tab, so Tab is not sent as being pressed for rofi.
(On Wayland, there is no such grab, so the Tab key is actually sent, with the Alt modifier down, and it works.)

There may have been an underlying bug with Alt and Super modifiers, which I found by checking for your issue, and should be fixed by now.

[sergei-dyshel]

@sardemff7
Thanks for helping me! Unfortunately, for some reason using -kb-accept-entry !Alt+Alt_L doesn't seem to work always. I work with multiple monitors and tried to check this behaviour with different combinations of active monitor / active window / mouse position
However, I've noticed that this is somehow related to dual monitor setup I'm using. When I switch to some window and then move mouse to other monitor and press Alt+Tab, Rofi works a couple of times in a row as expected but then it stops working for some reason. After doing this procedure again, Rofi starts working again. Also, the only working option is -monitor -5 (the default).

This is very frustrating, especially when I'm so close 😞 . Is there a command line switch to dump all key events so I can try debugging this issue? Where is relevant code in Rofi?

BTW, can it be connected to the bug you've fixed?

Also there some weird issue with the order of windows (when running with -show window). Usually active window is the first item in the list (so pressing Alt-Tab does nothing) but sometimes previous window is first item in the list so Alt-Tab switches it correctly.

[DaveDavenport]

Also there some weird issue with the order of windows (when running with -show window). Usually
active window is the first item in the list (so pressing Alt-Tab does nothing) but sometimes previous
window is first item in the list so Alt-Tab switches it correctly.

Please don't report unrelated issues in comments of issues. Please create a new issue.

[sardemff7]

However, I've noticed that this is somehow related to dual monitor setup I'm using.

You mean it works as expected if you use only one monitor?
To be completely clear, it works:

• if you use 1 monitor and !Alt-Alt_L
• if you use 2+ monitors and any on-press keybinding (e.g. Return)

and it does not work:

• if you use 2+ monitors and use on-release binding (one that works with 1 monitor, e.g. !Alt-Alt_L)

is that what you say?

[sergei-dyshel]

@sardemff7
Ok, I've played with it a little more and it seems that !Alt-Alt_L binding doesn't work properly without any relation to dual monitor. I've disabled second monitor and still observe this issue. Sometimes it works, sometimes not, I see that it somehow depends on which window is active now and where is mouse cursor but can't figure out any pattern right now.

[sergei-dyshel]

on-press keybindings work flawlessly

[sardemff7]

It looks like it's related to the #38, namely the focus is following the mouse and it happens to work when the mouse is where rofi appears
Hopefully fixed with the focus steal hack

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.