my customer would like to have layers menu always visible, loaded to some div instead of appearing in popup on click on action button.
That is currently not possible unless through a modification. You could head on over to the feature request forum and add a request for this feature along with why it would be useful.
we need it for specific customer needs.
are you doing such stuff as custom development too? if yes - can you send me price and expected time to firstname.lastname@example.org?