It would be nice if $window().pbstate & $window().pbpercent was extended to support dcc windows via:
Code
 $window(@ $+ $send(1).wid).pbstate
 $window(@ $+ $send(1).wid).pbpercent
 $window(@ $+ $get(1).wid).pbstate
 $window(@ $+ $get(1).wid).pbpercent

The code i'm using already has the wid & this would save me having to figure out which wid is a which dcc.