Code for this is http://www.w3schools.com/jsref/tryit.asp?filename=tryjsref_onmouseover
See forum posting: https://productforums.google.com/forum/#!category-topic/sites/LjvdxpZ2YgQ
The code when put into an HTML Box doesn't work (at least for me it doesn't).
I get the error: 'folding element body into parent' on the firet line of the code
The same code when put into a gadget works.