I hope this isn't another embarrassing error on my part
I have a script that opens a popup window. But in Firefox, for some reason on the first load I get this error:
Using Firebug to do the stack trace, it's always coming from a line where I use getEl(). The weird thing is that it works if I refresh the page (F5 since I hide the toolbars), and it works just fine in Opera that I just tested. It's always that initial load on the popup and only in Firefox.
this.fireVisibilityChanged.createDelegate is not a function