
C-F doesnt detect file patterns. It detects only folders.
The issue is in this regular expression:
copycat.tmux
if stored_search_not_defined "$file_search"; then
tmux set-option -g "${COPYCAT_VAR_PREFIX}_${file_search}" "(^|^\.|[[:space:]]|[[:space:]]\.|[[:space:]]\.\.|^\.\.)[[:alnum:]~_-]*/[][[:alnum:]_.#$%&+=/@-]*"
fi