Mask does not work in HTML5

Help
#1

If add Bitmap at Sprite and set mask on Sprite, mask not work.
Why?

#2

Also having problems with masks in html5.
Here is my example, that works for flash and native, but not for html5:

var s1:Sprite = new Sprite();
s1.graphics.beginFill(0xffffff);
s1.graphics.drawRect(0, 0, 200, 200);
addChild(s1);

var s2:Sprite = new Sprite();
s2.graphics.beginFill(0x000000);
s2.graphics.drawCircle(100, 100, 100);
s2.x = 75;
s2.y = 50;
s1.addChild(s2);
s1.mask = s2;

Result.
Flash:

HTML5:

haxelib list

actuate: [1.7.5]
admob: [1.1.0]
format: 3.1.1 [3.1.2]
haxelib_client: [3.1.0-rc.4]
hxcpp: 3.1.0 [3.1.39]
lime-tools: [1.5.7]
lime: 1.0.1 [2.0.0-beta]
nook-shop: [0.0.1]
openfl-samples: 1.3.0 [2.1.0]
openfl: 2.0.1 [2.1.5]
svg: [1.0.8]
swf: 1.5.2 [1.6.8]

Any help with that?
Thank you!