How to test is a movie clip is open?

I cannot find a function to know if a movie clip load by loadmovie(), is yet open or load.

I want to do this kind of stuff:

I would like to create a windowed flash.

I’ve got 3 buttons.
I’ve got 3 swf I want to load using these 3 buttons(fenetre1.swf, fenetre2.swf, fenetre3.swf.).
Each swf is a movie instance. This movie is composed by a image and a button to close the windows(action on the button unloadmovie(…)).

in my main fla file (the one with the 3 buttons)
at _level0:
I have create a empty clip:
clip1.createEmptyMovieClip(“movie1”, 10);
clip1.createEmptyMovieClip(“movie2”, 10);
clip1.createEmptyMovieClip(“movie3”, 10);

Inside a clip name clip1, I have created 3 buttons:
the code for each button is:

code for button1:
on (release) {
_root.x +=2;

code for button2:
on (release) {
_root.x +=2;

code for button3:
on (release) {
_root.x +=2;


the pbl is to avoid to re-open a clip which is already open.
I look for an if statment in order to know if the clip is not already open or if it open.
If it is open I not load the movie and I only make a swapdepth
If it is not I load the movie and swap the depth to bring him to front.

The _visible function always return 1(loadded or not)
Help me !!!

Why this._visible = False;
no more works on mx pro 2004 since it did on flash5.