Phase 3: Modern Features

Objective

Enable tmux 3.2+ features that the installed tmux 3.6a supports. These are added in a new 05_SNIPPETS/modern-features.conf with version-conditional loading.

Features Enabled

Feature Purpose

Feature	Purpose
`extended-keys on`	CSI u mode — proper modifier key support (Ctrl+Shift, Alt+Shift pass through correctly to nvim and other TUI apps)
`allow-passthrough on`	Enables image protocols (kitty graphics, sixel) and OSC 52 clipboard integration
`popup-border-lines rounded`	Rounded corners on `display-popup` windows
`popup-border-style 'fg=#8b5cf6'`	Purple border matching the aethelred theme accent color
`copy-command 'wl-copy'`	Native Wayland clipboard integration for copy mode

extended-keys on

CSI u mode — proper modifier key support (Ctrl+Shift, Alt+Shift pass through correctly to nvim and other TUI apps)

allow-passthrough on

Enables image protocols (kitty graphics, sixel) and OSC 52 clipboard integration

popup-border-lines rounded

Rounded corners on display-popup windows

popup-border-style 'fg=#8b5cf6'

Purple border matching the aethelred theme accent color

copy-command 'wl-copy'

Native Wayland clipboard integration for copy mode

Loading Strategy

Version-conditional source in tmux.conf:

if-shell '[ "$(tmux -V | cut -c6- | cut -d. -f1)" -ge 3 ]' \
    'source-file ~/.config/tmux/05_SNIPPETS/modern-features.conf'

This ensures portability — the config still works on older tmux versions without errors.