I've found this answer in fckeditor forum:
>The problem is that when FCKeditor is created from a textarea which is not yet
>visible, it is given a height and width of 0. This appears to be true whether
>you define >a width and height or not.
>I have two solutions. The first (easiest) is to not load up the Tabs code
>until /after/ the FCKeditor instances have been displayed on screen. This is
>usually okay, as >it should only take a millisecond or so for the browser to
>figure out all the proper widths and heights, then you can run the Tabs code.
I've tried to launch:
$('#tabcontainer').tabs();
in firebug console, after the page is fully loaded, and it works.
But How can I test that all fckeditor instances are fully loaded? I've
tried con windows.load, but it doesn't works, maybe cause every
Fckeditor istance is in a iframe?
How can I test that all iframes are fully loaded?
thank you