Flex application security error on Fullscreen mode

Have spot this error when I tried to implement fullscreen mode on my Flex app.

Here is my fullscreen toggler:

        private function toggleFullscreen():void {
            try {
                switch (stage.displayState) {
                    case StageDisplayState.FULL_SCREEN:
                        /* If already in full screen mode, switch to normal mode. */
                        stage.displayState = StageDisplayState.NORMAL;
                        stage.fullScreenSourceRect = appRectangle;
                        break;
                    default:
                        /* If not in full screen mode, switch to full screen mode. */
                        stage.displayState = StageDisplayState.FULL_SCREEN;
                        appRectangle = stage.fullScreenSourceRect;
                        stage.fullScreenSourceRect = new Rectangle(0, 0, 1000, 750);
                        break;
                }
            } catch (err:SecurityError) {
                // ignore
                Alert.show('Cannot go full screen');
            }
        }

When I press fullscreen icon I’ve got this exception.
The problem was simple – you need to allow your app go to fullscreen mode like this:

        <param name="allowFullScreen" value="true" /> - in the <object>
        allowFullScreen="true" - in the <embed>