Panel collapse/expand is choppy
When working on issue #10364 I noticed that collapse/expand animations could be weirdly choppy.
The attached recording was made in the widget gallery using the bootstrap3 theme: https://www.webtoolkit.eu/widgets/layout/grouping-widgets?theme=bootstrap3
I can fix this by revising the animation functions in
WWebWidget.js (see attached patch). A video of the resulting proper animation is also attached.