Tmux is one of the most useful tool when it comes to using a linux terminal.

Tmux is a terminal multiplexer, it allows a user to access multiple terminals (or windows), each running a separate program, while providing a single screen to work on. Tmux is useful for running more than one command-line program at the same time, increasing productivity and the way you work.

In case you are connected to multiple monitors or using a multiple devices to access the same tmux window, then, there are high chances that your tmux window is now set to the most recetly used window size. The window looks cropped and you will have to resize it to bring it back to full-screen.

This works for the latest version of tmux.

Resize tmux window to full screen

First make sure you are attached to a tmux session and active on a tmux window.

Then, you will have to run the Prefix followed by :resize-window -A to resize the window to full screen or the largest connected session.

Prefix
:resize-window -A

By default the prefix is Ctrl-B, so to resize the tmux window to full screen you can run the following command-

Ctrl-B
:resize-window -A

I hope this tutorial for resizing the tmux window to full screen was useful. You can also check out the complete tmux cheatsheet of keyboard shortcuts and mouse shortcuts.