tmux powerline sync segment

colorschemes_default.json

# config_files/colorschemes/default.json

...
"synchronized_panes":         { "fg": "red", "bg": "gray0", "attrs": [] }
...

segments_tmux.py

# segments/tmux.py

def synchronized_panes(pl):
	'''Return "SYNC" if the panes of the current window are synchronized
	'''

	synced_output = get_tmux_output(pl, 'display-message', '-p', '#{pane_synchronized}')
	if not synced_output:
		return None
	synced = synced_output.rstrip().split('\n')[0]

	return None if synced == "0" else "SYNC"

themes_tmux_default.json

# config_files/themes/tmux/default.json

"right": [
		{
		"function": "powerline.segments.tmux.synchronized_panes",
		"priority": 50
		},
		...