'wakeOnTouch' for Bangle.js 2

Hi,
I'm trying to get a 'Bangle.js 2' to wake up whenever the screen is touched.

I've isolated my code into this silly test app :

var dummy = 0;
g.clear().setFontAlign(-1,-1).setFont("Vector",20).drawString("Hi",10,10);

Bangle.setOptions({wakeOnTouch:true});

Bangle.on("touch", function() {
  Bangle.buzz(100,1);
  g.clear();
  g.drawString((++dummy).toString(), 10, 10);
});

Touch events are properly captured when the device is awake, but once it sleeps (dim LED backlight), no further events are thrown. Only after a BTN1 click, events are recognized again.

The wakeOnTouch option seems to be properly set :

Bangle.getOptions()
={ gestureStartThresh: 640000, gestureEndThresh: 4000000, gestureInactiveCount: 4, gestureMinLength: 10,
  stepCounterThresholdLow: 32, stepCounterThresholdHigh: 78149, twistThreshold: 819, twistTimeout: 1000, twistMaxY: -800,
  wakeOnBTN1: true, wakeOnBTN2: true, wakeOnBTN3: true, wakeOnFaceUp: false, wakeOnTouch: true,
  wakeOnTwist: true, powerSave: false, lockTimeout: 10000, lcdPowerTimeout: 0, backlightTimeout: 10000 }
>process.env
={
  VERSION: "2v09.120",
  GIT_COMMIT: "8c650226b",
  BOARD: "BANGLEJS2",
  FLASH: 1048576, SPIFLASH: 8388608, HWVERSION: 2, STORAGE: 8388608, RAM: 262144,
  SERIAL: "5705650f-3ec9f6bf",
  CONSOLE: "Bluetooth",
  MODULES: "Flash,Storage,heatshrink,locale",
  EXPTR: 536884176 }
>

Is this expected behavior ? What am I missing ?

Thanks