Background transparency not working properly for Window Title Widgets

[lealoureiro]

I am not requesting help with my configuration and believe something is genuinely broken.

• [x] Something is really actually broken.

Is there an existing issue outlining your problem?

• [x] I have searched the existing issues and troubleshooting guide, and they do not solve my problem.

Describe your problem.

I'm having a small issue catppuccin for tmux when using transparency. For Windows title widget, there is still a bit of background that is not transparent:

The interesting part is that on right side is working properly. Any what could be or where to look at?

Paste your configuration.

set-option -g default-terminal 'screen-256color'
set-option -g terminal-overrides ',xterm-256color:RGB'

set -g status-position top
set -g prefix ^A
set -g base-index 1
set -g history-limit 1000000
set -g renumber-windows on
set -g set-clipboard on
set -g default-terminal "${TERM}"
set -g mouse on


set -g @plugin 'tmux-plugins/tpm'
set -g @plugin 'tmux-plugins/tmux-sensible'
set -g @plugin 'catppuccin/tmux'

set -g @catppuccin_flavor "mocha"
set -g @catppuccin_window_status_style "rounded"
set -g @catppuccin_window_left_separator ""
set -g @catppuccin_window_right_separator " "
set -g @catppuccin_window_middle_separator " █"
set -g @catppuccin_window_number_position "right"
set -g @catppuccin_window_default_fill "none"
set -g @catppuccin_window_default_text "#W"
set -g @catppuccin_window_current_fill "none"
set -g @catppuccin_window_current_text "#W#{?window_zoomed_flag,(),}"
set -g @catppuccin_status_modules_right "directory" # date_time"
set -g @catppuccin_status_modules_left "session"
set -g @catppuccin_status_left_separator  " "
set -g @catppuccin_status_right_separator " "
set -g @catppuccin_status_right_separator_inverse "no"
set -g @catppuccin_status_connect_separator "no"
set -g @catppuccin_directory_text "#{b:pane_current_path}"
set -g status-right-length 100
set -g status-left-length 100
set -g status-left ""
set -g status-right "#{E:@catppuccin_status_application}"
set -ag status-right "#{E:@catppuccin_status_session}"
set -ag status-right "#{E:@catppuccin_status_uptime}"

run '~/.config/tmux/plugins/tpm/tpm'

# Override status bar background for transparency (must be after plugin load)
set -g status-bg default
set -g status-style bg=default


### Attach screenshots.

![screenshot](https://i.ibb.co/CsP2VtNj/Screenshot-2025-12-20-at-13-33-13.png "screenshot")


### What tmux version are you seeing the issue on?

tmux3.5a

### What shell are you using?

zsh

### Any additional comments?

_No response_