You could also use the system action "Create object".
Normally creating and destroying object without reusing them is not that great for HTML5, but C2 behind the scene recycles the objects, however I still think it is better to have the window created once and to reuse it, but that is not a big deal at the end for that.
EDIT: Also opacity = 0 isn't slowing down the device more than opacity = 100 I think, but setting it to invisible tells C2 to skip entirely the drawing on screen, which is better
At the end C2 isn't that limited, the only limitations really seems to be the HTML5 ones, and all in all it is still easier in C2 since it helps a lot and is already well optimised for a lot of things (like the recycling of objects to compensate the lack of direct memory management of javascript, or the bounding box collision checks to prevent doing too many precise collisions checks if not needed)