Error this.xHdr.insertRow is not a function

Suite and Optimus Suite 5
#1

I get this error this.xHdr.insertRow is not a function from firebug when I try to view my grid in Firefox. Anyone know whats causing it?

#2

The only possible reason of problem - the container used as source of grid is not attached to DOM at all ( some kind of node which was created, but not attached to DOM ) , in such case grid initialization may fail.

#3

I have grid initialized as

how do I check if it is attached to the DOM