Add total size of the selected files/directories somewhere in the status bar?

[jpggithub]

I would like to always display the total size of the selected files/directories somewhere in the status bar.

Inspired by #1214 (comment), I tried:

cmd on-select %du -ch $fx | tail -n 1 | cut -f 1

but it deletes the information displayed at the bottom left each time I move the selection (because a new file/directory is selected by default at each move).

Is there any way of displayed the total size of selected files/directories without deleting something?
It could be an option for the ruler ? (for example next df)

[joelim-work]

You can use user-defined options to store custom data and display it in the ruler:

cmd on-select &{{
    result="$(du -ch $fx | tail -n 1 | cut -f 1)"
    lf -remote "send $id set user_du $result"
}}

set rulerfmt '  %{lf_user_du}|  <everything_else>'

[jpggithub]

Thank you (even if I have to wait the r31 version in Debian Testing to see the rulerfmt in the manual ;-)