Collision stops

[Moonbox]

Hi, I'm building a game in Phaser but I came along a strange bug. Whenever I'm testing the game and I open the developers tools (or another action like 'right click > copy image'), my character stops colliding with the tile map. This also seems to happen sometimes when I change the desktop on my mac. I searched a long time but can't seem to fix it. Any ideas?

Here is my code:

var mainState = {	preload: function(){		game.load.tilemap('map','assets/tilemap.json', null, Phaser.Tilemap.TILED_JSON);		game.load.image('tileset','assets/tileset.png');		game.load.atlas( 'atlas', 'assets/atlas_char.png', 'assets/atlas_char.json' );	},	create: function(){		game.physics.startSystem(Phaser.Physics.ARCADE);		game.stage.backgroundColor = '#dadada';		game.world.bounds.setTo(0,0,1200,800);			this.player = game.add.sprite(45,670,'atlas');		game.physics.arcade.enable(this.player);		this.player.body.collideWorldBounds = true;		this.player.body.gravity.y = 250;				this.createWorld();		game.camera.follow(this.player);		this.cursor = game.input.keyboard.createCursorKeys();		game.input.keyboard.addKeyCapture([Phaser.Keyboard.UP, Phaser.Keyboard.DOWN, Phaser.Keyboard.LEFT, Phaser.Keyboard.RIGHT]);	},	update: function(){		game.physics.arcade.collide(this.player, this.layer);	},	createWorld: function(){		this.map = game.add.tilemap('map');		this.map.addTilesetImage('tileset');		this.map.setCollision(1);		this.layer = this.map.createLayer('Tile Layer 1');				this.layer.debug = true;		this.layer.resizeWorld();	}};var game = new Phaser.Game(800, 500, Phaser.CANVAS, 'gameDiv');game.state.add('main',mainState);game.state.start('main');