Weird behaviour on show/hide layers all of a sudden
A site I built a while ago has recently started behaving weirdly.
I used show/hide layers to make several rollover maps, and now the rollover layers all seem to be sliding up and down and all over the place. Before they were just showing normally, in place, on mouseover.
See this page for example: http://www.thehaymarketedinburgh.com/the-haymarket/site-plan/
Rollover the buildings and the highlight appears to slideup from the bottom of the browser, where before, and for months, it didn't. If you hover the mouseover the behaviours eventually go all out of whack. The code hasn't been changed. Any idea what could be causing this?