Which keys are pressed during the Alt+Tab Swapper action

[ziombo]

I believe I'm using a slightly older implementation than what you currently have, but the new one seems to be just a wrapper.

Mine

ZMK_BEHAVIOR(swapper, tri_state,
    bindings = <&kt LALT>, <&kp TAB>, <&kt LALT>;
    ignored-key-positions = <LT2>;
)

Current

ZMK_TRI_STATE(swapper,
    bindings = <&kt LALT>, <&kp TAB>, <&kt LALT>;
    ignored-key-positions = <LT2>;
)

I'm wondering what exactly happens in terms of keypresses when I trigger the above. I'm asking because I recently started using Parsec (remote desktop, but for gaming so the latency and quality are great) to connect to my work laptop and it has an 'Immersed' mode in which even the alt+tab action is passed into the remote machine. In other words when pressing alt+tab instead of switching from Parsec window to the next one on my local pc, I can switch between programs on my work laptop to which I'm connected. Using alt+tab directly works without issues.

However there seems to be an issue when using the swapper. The first time I press the swapper key it doesn't trigger alt+tab inside parsec and instead a normal Tab is received. The second time I do it it works as expected. So that's why I'm asking about the swagger's course of action and keypresses. Also holding down the swapper key will result in a Tab keypress and then switching windows.

Based on the config <&kt LALT>, <&kp TAB>, <&kt LALT> will toggle LALT, then press TAB and then release LALT? Would you have any ideas why would the first press be registered as just Tab?

[urob]

This is the key events it sends:

• press &kp LALT (when behavior starts)
• press and release &kp TAB (when behavior starts & then again each time you press &swapper)
• release &kp LALT(when behavior ends)

[ziombo]

My first thought is that maybe the delay between first LALT and TAB is too small so it doesn't register it correctly. Is the delay between those actions configured somewhere and would it be possible to take control over that?

[urob]

tri-state itself doesn't have a way to delay the tab. But you could try replacing the first or second binding with macro that adds a gap.

Replacing the second binding with a macro that adds a gap before TAB should work for sure at the expanse of adding it also for subsequent TAB-presses. Replacing the first binding with a macro that adds a gap after the LALT wouldn't have that drawback but I'm not a hundred percent sure this would succeed in delaying triggering the second binding.

[ziombo]

Is this what you have in mind

ZMK_BEHAVIOR(delayed_tab, macro,
    wait-ms = <500>;
    tap-ms = <5>;
    bindings = <&kp TAB>;
)

// Alt+Tab swapper, requires PR #1366
ZMK_BEHAVIOR(swapper, tri_state,
    bindings = <&kt LALT>, <&delayed_tab>, <&kt LALT>;
    ignored-key-positions = <LT2>;
)

I see the delay in general, but it hasn't affected the issue, still on first swapper use the tab is received without the ALT.

By some trial an error I managed to find something that makes it work and seems to be working like the original swapper:

ZMK_BEHAVIOR(delayed_tab, macro,
    wait-ms = <10>;
    tap-ms = <1>;
    bindings = <&kp LALT>
             , <&kp TAB>;
)

// Alt+Tab swapper, requires PR #1366
ZMK_BEHAVIOR(swapper, tri_state,
    bindings = <&kt LALT>, <&delayed_tab>, <&kt LALT>;
    ignored-key-positions = <LT2>;
)

so basically an additional keypress of LALT and since it's already toggled I don't think it makes any difference. Unless you see an obvious issue with that I'd treat the issue as solved

[ziombo]

Unfortunately it seems that the LALT signals aren't ending properly , but I think that's the general direction for me to look into. Thanks for the help (also thanks for chiming in on my question on ZMK discord 😄 )

[urob]

Yea, that looks a bit weird. Effectively you are getting:

• Press LALT when the behavior is first invoked
• Press LALT again and then release it on every subsequent behavior tap
• Release LALT when the behavior is released.

I think the other approach to delay the tap might be more promising. The problem is that afaik wait-ms only operates in between macro actions. Not sure if there is a more elegant way but you could try adding a dummy event at the beginning to get around that. Maybe something like this works?

ZMK_BEHAVIOR(delayed_tab, macro,
    wait-ms = <500>;
    tap-ms = <5>;
    bindings = <&none &kp TAB>;
)

// Alt+Tab swapper, requires PR #1366
ZMK_BEHAVIOR(swapper, tri_state,
    bindings = <&kt LALT>, <&delayed_tab>, <&kt LALT>;
    ignored-key-positions = <LT2>;
)

[ziombo]

Sorry for the long delay. This appears to be working and the crucial part is the wait-ms setting, too short and it doesn't catch the combo. Thanks again!