Could not find symbol 'mLayout' (DataField, BehaviorDelegate)

Hello,

i'm trying to find an drawable by id in the onTap-Event of BehaviorDelegate.


But the findDrawableById("center"); throws every time an "Could not find symbol 'mLayout' error."


class MyDataFieldInput extends WatchUi.BehaviorDelegate {

function initialize() {
BehaviorDelegate.initialize();
System.println("init");
}

function onTap(clickEvent) {
var center = View.findDrawableById("center");
center.setColor(Graphics.COLOR_BLUE);

System.println("Tap: " + clickEvent.getCoordinates() + " -> " + clickEvent.getType());

return true;
}

}

Can anyone help me, please?

PS: I found this topic: https://forums.garmin.com/forum/developers/connect-iq/142524- but it don't helps me ...