I’m on a project right now that’s using TweenLite But it’s missing the isTweening method. Here it is:

First update the constructor:
Line 180/181 should look like this:

_all[$target][this] = this;
_all[$target]['instance'] = this;

In the executeAll() function, there is an innter for loop, change it to this:

for (twp in a[p]) {
 if(twp == 'instance')
  continue;
 tw = a[p][twp];
 if (tw != null && tw.active) {
 tw.render(t);
 }
}

Then add this somewhere at the bottom:

public static function isTweening(target:*):Boolean
{
  if(_all[target] == null)
    return false;
  var t:* = _all[target] as Dictionary;
  var instance:TweenLite = t['instance'] as TweenLite;
  return instance.active;
}

Hope that helps someone out there.