Add broadcast support for multi-pane syncronization

[dave92082]

What do you want to change?

Hello, I have been using Ghostty for a while now and have wanted a very simple way to sync/unsync input to multiple panes together similar to tmux and iterm2. Looking through the closed issues and discussions I found discussion #3227 and took a swing at an implementation.

I wanted the following features:

1. Group panes together very easily ( cmd + shift + click )
2. Ungroup panes very easily ( same shortcut)
3. Support multiple groups
4. Make synchronized panes easily identifiable using a colored border

Why do you want to make this change?

I often times need to quickly run the same commands on several terminal windows either as part of a workflow or even just setting up an environment. I have a tmux script that works well for this but clicking a pane is a much nicer experience

I acknowledge that:

• I have read the Contributing Guide and understand the contribution process.
• I have read and agree to follow the AI Usage Policy.
• I wrote this vouch request myself, in my own voice, without AI generating it.

[jcollie]

This is an interesting proposal. I like 1 and 2 but I'd like to know what sort of UI/UX you suggest for 3? 4 is relatively straightforward on GTK (I have something mocked up in an unreleased branch).

[jcollie]

Also, 1 and 2 should be doable strictly with the keyboard as well.

[dave92082]

Here's how I have it for 3:

Screen.Recording.2026-08-10.at.6.53.14.PM.mov

[dave92082]

All groups are identified by a color. Adding new groups change the color so it's clear and currently 6 groups of panes are allowed. You can also group panes in different windows together as well.

[jcollie]

What's the key/mouse sequence for changing the group?

[dave92082]

There is not a sequence for changing the group. You remove a grouped pane (cmd + shift + click again), select any pane in the desired new group, and then cmd + shift + click again.

The idea is to be able to quickly group a few panes and then ungroup them just as fast. I'm thinking through key bindings for a keyboard only grouping that would be as fast as holding down cmd + shift and clicking several panes.

[jcollie]

!vouch

[jcollie]

FYI, we're getting close to releasing 1.4, so this will not go in before that as I suspect that some of the changes will be non-trivial.

[dave92082]

I have an implementation that's pretty clean for mouse only. I'll add in the keyboard only mechanism tonight and get the PR open. Looking at the current keybindings in 1.3.2-main, I'm thinking Super + Shift 1 through 0 and expand my implementation to support 10 groups instead of the current 6