You don't have to destroy anything, just change the component's 'visible' property to false to hide it. Or you can use states.
But... if I want to destroy the popup opened, can't i?
One time opened, I cant close it anymore ? Change the visibility seens not the best solution.
You don't have to destroy the component manually, flex does that for you if you use states.
Check out this video tutoriral on states by Adobe: http://www.adobe.com/devnet/flex/videotraining/xml/vid31.html
If I may not destroy a popup, why there is the PopUpManager.removePopUp method ??
The method PopUpManager.removePopUp exists just to close, remove ("destroy") the popup...
How can I solves this problem reported above? I dont want to hide... I want to close it and open again other undefined time.
popup manager has two methods just for that purpose,
if you want to reuse instance you call addPopup if you want to instantiate on every "pop" you call createPopup.
removePopup removes it from displayList it does not destroys it, actually there is no way to destroy instance