Issue description

Run these commands (easiest way is in a script):

tmux split-window -v
tmux split-window -h
tmux split-window -v
tmux resize-pane -y 999

Expected behavior: The final pane should be max height and the original pane should be minimum height
Actual behavior: The original pane size does not get resized

Required information

Please provide the following information:

• tmux version (tmux -V).
• Platform (uname -sp).
• $TERM inside and outside of tmux (echo $TERM).

tmux next-3.1
Linux unknown
xterm-256color

• Logs from tmux (tmux kill-server; tmux -vv new).

I have no idea how to grab the relevant snippet.