Ctrl+[ send ANSI escape sequence ^[[91;5u, and not ^[ like normal Escape key.

[magnusriga]

^[ in ZSH, i.e. the Escape ASCII code which I use to enter Normal mode (vicmd) from Insert mode (viins), will undo everything that was just entered in Insert mode.

Are others seeing the same behavior? Is there any way to change that behavior, so entering Normal mode with ^[ keeps what was inserted?

Note that the regular ESC key on the keyboard, i.e. not ctrl+[, works without undoing what was just inserted, and I have yet to figure out why the two differs. I was under the impression that ESC actually just sends ^[ to the terminal, under the hood.

It does not happen in e.g. Wezterm.

[magnusriga]

To add to the above, I changed the keybinding for ^[ in ZSH to self-insert, to see what ANSII escape sequence the terminal converts the keystroke into.

Turns out, in ghostty ^[ is actually sent as ^[[91;5u, whereas the keyboard Escape key sends the expected sequence ^[. Here is a screenshot:

Further research reveals that an ANSII sequence "...containing the parameter bytes <=>? or the final bytes 0x70–0x7E (p–z{|}~) are private", i.e. "...so that terminal manufacturers could insert their own sequences without conflicting with the standard. ".

In other words, ^[[91;5u, is a private sequence defined by ghostty.

Googling that sequence however, shows that e.g. Mintty has an option to turn usage of ^[ as ctrl+[ on/off, which follows from this xterm discussion.

In the ghostty source code, the behavior above is tested, albeit marked as legacy, thus it seems to be intended behavior by the developer.

Is there a way to turn that feature off, so ^[ is treated as just ^[?

[magnusriga]

In the xterm discussion linked above, where , there is a link to a proposed solution called "fixterm", to distinguish Esc from ^[ (if I understand it correctly). That word, fixterm, is also used in the ghostty code snippet linked to above.

I initially hacked around the issue by forcing ghostty to send ^[ when hitting ctrl-[, by using the key binding keybind = ctrl+[=text:\x1b. That smells like a bad solution however, as I am sure the distinction was made for a reason.

Thus, I moved over to mapping ^[[91;5u to the vi-cmd-mode widget in ZSH, with keybind -M viins '^[[91;5u' vi-cmd-mode. An added benefit of this solution, is there is no delay from KEYTIMEOUT in ZSH, due to ^[ being a prefix to other sequences.