function showPopup (targetObjectId) {
	if(targetObjectId!=window.currentlyVisiblePopup) {
	if( changeObjectVisibility(targetObjectId, 'visible') ) {
	    window.currentlyVisiblePopup = targetObjectId;
	    return true;
	} else {
	    return false;
	}
    } else {
	return false;
    }
}


function hideCurrentPopup() {

	if(window.currentlyVisiblePopup) {
	changeObjectVisibility(window.currentlyVisiblePopup, 'hidden');
	window.currentlyVisiblePopup = false;
    }
}