diff --git a/spine-ts/webgl/demos/spritesheet.js b/spine-ts/webgl/demos/spritesheet.js
index 58a5dd323..d8a8c74a8 100644
--- a/spine-ts/webgl/demos/spritesheet.js
+++ b/spine-ts/webgl/demos/spritesheet.js
@@ -103,6 +103,8 @@ var spritesheetDemo = function(loadingComplete, bgColor) {
 		timeKeeper.update();
 		var delta = timeKeeper.delta;
 
+		resize();
+
 		delta *= timeSlider.get();
 		if (timeSliderLabel) {
 			var oldValue = timeSliderLabel.textContent;