Added in 1.9.4
See also Monitor Panels.
name - The panel name to check. (Server, Channel, Private, Url, Notify, Dcc, Highlight or Treebar)
.wid - Returns the window id of the panel if any.
; Display information about the highlight panels. //echo -ag Higlight is $iif($dockpanels(Highlight), Visible, Hidden) ; Hide the highlights dockpanel if it's in a window. //window -h @ $+ $dockpanels(Highlight).wid