@Condor,thank you for reply!
My code in FF3 has all the effect what I need.
1)My form.xf.CheckerInfoDisplayForm is a custome component that show plain html table, in IE7 the form is not display sometimes or leave the display area blank!
2)But why in FF3 it is ok?
3)A layout:'slide' with easing:'none' still has the slide effect!