Qt Particle Flicker when controlled by JoystickControllerHUD

Hi all,

as a followup to https://felgo.com/developers/forums/t/free-particles-influenced-by-entity-rotation/ issue I tried the Qt particle system. While the original issue is fixed now a new problem arose. I want to control the emission rate via a JoystickControllerHUD. For the first few movements of the controller the particles start flickering. Afterwards, the particles are peramenently visible.

Here is some example code:

import Felgo 3.0
import QtQuick 2.0
import QtQuick.Particles 2.0

GameWindow {
    id: gameWindow
    activeScene: scene
    width: 960
    height: 640

    ParticleSystem {
      id: particleSys
      width: gameWindow.width
      height: gameWindow.height
      z: 10
      
      ImageParticle {
	id: smoke
	system: particleSys
	anchors.fill: parent
	groups: ["A"]
	source: "img/particle.png"
	colorVariation: 0
	color: "#00111111"
      }
      
    }

    Scene {
        id: scene
        width: 480
        height: 320

	Rectangle {
	  id: background
	  anchors.fill: parent
	  color: "black"
	}

	Rectangle {
	  id: testParticles
	  x: 200
	  y: 100
	  width: 10
	  height: 3
	  rotation: 0.0
	  color: "blue"
	  visible: true

	  Emitter {
	    system: particleSys
	    group: "A"

	    anchors.fill: parent

	    emitRate: 500
	    lifeSpan: 350

	    acceleration: PointDirection { y: 0; xVariation: 0 }
	    velocity: PointDirection {x: -300; y: 300}
	    
	    size: 24
	    sizeVariation: 8
	    endSize: 10
	  }
	}

	Rectangle {
	  id: controlledParticles
	  x: 400
	  y: 100
	  width: 10
	  height: 3
	  rotation: 0.0
	  color: "blue"
	  visible: true
	  property double force: 0.0

	  Emitter {
	    system: particleSys
	    group: "A"

	    anchors.fill: parent

	    emitRate: 500 * controlledParticles.force
	    lifeSpan: 350

	    acceleration: PointDirection { y: 0; xVariation: 0 }
	    velocity: PointDirection {x: -300; y: 300}
	    
	    size: 24
	    sizeVariation: 8
	    endSize: 10
	  }
	}

	JoystickControllerHUD {
	  id: joystick
	  anchors.bottom: parent.bottom
	  anchors.left: parent.left
	  anchors.bottomMargin: 15
	  anchors.leftMargin: anchors.bottomMargin
	  width: 120; height: 120

	  source: "img/joystick_background.png"
	  thumbSource: "img/joystick_thumb.png"

	  onControllerXPositionChanged: controlledParticles.force = calcForce();
	  onControllerYPositionChanged: controlledParticles.force = calcForce();

	  function calcForce() {
	    return Math.sqrt(Math.pow(controllerXPosition, 2.0) + Math.pow(controllerYPosition, 2.0))
	  }
	} // joystick
    }// scene
}

Any ideas?

Cheers,

Thomas