WebAnimator persistence?

Web 1.0 (2019r1)
I created a simple test webapp with a webcontainer. I have 2 Buttons.

Button 1 calls a method which embeds a small container within the large container.
Appropriate code allows this small container to be dragged & dropped anywhere within the parent container. No surprises - all works fine.

Button 2 calls a similar method, but this method also animates the new small container so that the new small container appears to slide in from the left of view. No surprises - works as intended.

Here comes the “but” !
If I now drag any small container which was created via Button 2, the “Drop” will animate the small container to its new position! (My expectation would be that Drag 'n Drop would NOT include any animation). It’s as though any object which has been animated seems to remain animated through any subsequent drag / drop movements??
How can I de-couple the animator from the embedded object after the initial animation??