Byobu resize panes up, down, left, right

Press Ctrl + a and type :resize-pane followed by a direction flag. Optionally, include a distance.

Use one of the following resize-pane commands to resize:

:resize-pane -D
:resize-pane -U
:resize-pane -L
:resize-pane -R

To increase the amount of resize, include a number after the direction flag:

:resize-pane -D 20
:resize-pane -U 20
:resize-pane -L 20
:resize-pane -R 20