Not working with ActionScript 2 component.
By: Josh Knight
I hope someone will find this sooner than I did.
There's a known Flash bug that breaks the functionality of the removeMovieClip() function in Flash when using getNextHighestDepth() function. Apparently, if you have an AS2 component on the stage and attempt to use these functions, they may not work - something about the component reserving that depth for some reason.
Anyway, if this is happening to you, try first using swapDepths() to swap the item to be removed with a higher depth - maybe 10000 or so. Then try removing the clip. Something like this:
this.button_btn.onRelease = function() {
_root.newClip_mc.swapDepths(1048575)
removeMovieClip(_root.newClip_mc);
};
Here's more info from Adobe
I hope that helps someone.
Josh