detect old or new tmux mouse support and use proper options accordingly

.tmux.conf

@@ -303,17 +303,34 @@ run 'for name in $(printenv | grep -Eo ^tmux_conf_[^=]+); do tmux setenv -gu $na
 # }
 #
 # toggle_mouse() {
-#   old=$(tmux show -g | grep mouse | head -n 1 | cut -d' ' -f2)
-#   new=""
+#   if (tmux show -g -w |grep -q mode-mouse); then
+#     old=$(tmux show -g -w | grep mode-mouse | cut -d' ' -f2)
+#     new=""
 #
-#   if [ "$old" = "on" ] ; then
-#     new="off"
+#     if [ "$old" = "on" ] ; then
+#       new="off"
+#     else
+#       new="on"
+#     fi
+#
+#     tmux set -g mode-mouse $new \;\
+#          set -g mouse-resize-pane $new \;\
+#          set -g mouse-select-pane $new \;\
+#          set -g mouse-select-window $new \;\
+#          display "mouse: $new"
 #   else
-#     new="on"
-#   fi
+#     old=$(tmux show -g | grep mouse | head -n 1 | cut -d' ' -f2)
+#     new=""
 #
-#   tmux set -g mouse $new \;\
-#        display "mouse: $new"
+#     if [ "$old" = "on" ] ; then
+#       new="off"
+#     else
+#       new="on"
+#     fi
+#
+#     tmux set -g mouse $new \;\
+#          display "mouse: $new"
+#   fi
 # }
 #
 # battery() {