Thanks to Fredi Lange & Joan Bernaus

Be carefully, to increase de slider perfomance,
activate 'omit trace actions' in the publish settings

Interactions like "_width" and "_xscale" or "_height" and "_yscale" may cause problems

there a lot of ways to simplify the work width the function "movementTo",
look in the "combinations" label, to see some examples

movementTo()

movieClip: the movie who contains de variable or property

varName: the name of the variable or property, must be a quoted string, see the sample.

endVarValue: a number to reach, using sinusoidal or lineal transitions.

framesTotal: the number of frames to spend in the transition of the variable o property

kindOfMovement: specify "slide" or "linear", other movements like brake or accelarations, will be added soon, see the webpage or writeme

Example:
movementTo(_parent.myMovieClip, "_width", 600, 24, "slide");
movementTo(_parent.myMovieClip, "_height", Stage.height, 48, "linear");
movementTo(_parent.myMovieClip, "_x", 50, 48, "slide");

stopMovement()

USAGE:
stopMovement(movieClip, varName);

movieClip: the movie who contains the property or vale to stop

varName: the name of the variable or property, must be a quoted string, see the sample.

Example:
on (press, dragOver) {
  stopMovement(this, "_x");
  stopMovement(this, "_y");
  startDrag(this);
}