Hi Karl, Thank you for replying. It looks as animating tbody is not doable because of different display properties, while .show()/.hide() works just fine. I tried to animate it through mootools and Adobe Spry - it does not work.
Interesting that mootools make it work only in Firefox, not IE. The reason for that is that mootools wrap tbody into a div and animate that div. Obviously, it is an invalid structure for tables. Andy