Mouse support has issues when terminal does not support all modes.

[Imberflur]

Zellij requests the mutually exclusive mouse modes in order of least desired to most desired. https://github.com/zellij-org/zellij/blob/82f30e2cde5207e5b51301633686b2c7feac54f3/zellij-client/src/os_input_output.rs#L30

This relies on terminal emulators to ignore requests for unsupported modes and stay in the previous mode, which seems to be common behavior. In my instance, this works in Termux which doesn't support the any event mode (1003). However, mosh explicitly disables the previously enabled mode and only stores the most recent mode breaking this behavior. So when zellij sends the 1003 request it ultimately ends up disabling all mouse reporting.

I think this could be fixed by removing the explicit disabling of the current mode and storing all requested modes in the order requested so they can be played back in the right order on the client.

Testing

I tested the behavior of different mode requests via:

1. Open Termux -> mosh -> bash.
2. Run perl -E ' print "\e[?1002h\e[?1003h\e[?1006h" '
3. Move mouse (observe no characters printed).
4. Reset state: reset
5. Run perl -E ' print "\e[?1002h\e[?1006h" '
6. Move mouse (observe characters are print).

Repeating this outside of mosh printed character in step 3

[eminence]

I haven't looked at all into what Zellij is doing, but I did briefly attempt to reproduce your testing steps and after running the command from step 2 (using gnome-terminal), I see mouse movement stuff printed to screen as I move the mouse.

What version of mosh are you testing with?

[Imberflur]

What version of mosh are you testing with?

1.4.0

In gnome-terminal do you see mouse movement printed to the screen with just: perl -E ' print "\e?1003h\e[?1006h" '. If so, it at least partially supports the 1003 mode unlike Termux and won't have the issue I'm having in Termux.

[eminence]

perl -E ' print "\e?1003h\e[?1006h" '

I think there's a typo here, did you forget the [ from the first CSI?

Running perl -E ' print "\e[?1003h\e[?1006h" ' in gnome-terminal (outside of mosh) will cause mouse positions to be reported in SGR mode

[Imberflur]

I think there's a typo here, did you forget the [ from the first CSI?

Yes, good catch!