Dear ZoranB,
1- It sounds like you need a REGENALL command to update all vports.
2- The following code gets a layer name and sends all objects in the layer to back. The code defines a new command named LBACK.
(defun c:lback(/ lname ss)
(setq lname (getstring "\n Layer name: "))
(setq ss (ssget "x" (list (cons 8 lname))))
(command "draworder" ss "" "")
(princ)
)
Regards,
Farzad