micro editor shift+arrow shortcuts don't work

$ byobu --version
byobu version 5.112
tmux 2.8

$ micro --version
Version: 1.4.1
Commit hash: 1856891
Compiled on August 10, 2018

Micro Editor has default keybindings for Shift+arrow keys to extend current selection in the corresponding direction. See https://github.com/zyedidia/micro/blob/master/runtime/help/keybindings.md, Default Keybindings section.

When launching Micro Editor outside byobu-tmux, Shift+arrow keys work as expected.
When launching Micro Editor inside byobu-tmux with default configuration, Shift+arrow keys perform Byobu actions (switch focus between split panes).
When launching Micro Editor inside byobu-tmux with Shift+arrow keys unbound, Shift+arrow keys don't do anything.

Note: I unbound shift+arrow keys in byobu-tmux by putting these in ~/.byobu/keybindings.tmux

unbind-key -n S-UP
unbind-key -n S-DOWN
unbind-key -n S-LEFT
unbind-key -n S-RIGHT