CKEditor throws exception: 'n' is null or not an object

I have traced t开发者_运维问答he root of this exception to the sourcearea plugin of CKEditor v3.0.1. It occurs (occasionally) after the user has entered content into the editor and he then clicks on the small arrow in the upper right hand of the editor (close toolbar arrow). Has anyone seen this problem? We are using IE6.

onResize(){
   textarea.hide();  // EXCEPTION occurs because textarea is null
   textarea.setStyle( 'height', holderElement.$.clientheight + 'px');
   textarea.show();
};

After the problem begins (n = textarea = null), it occurs every time the right arrow is clicked.

As Pekka suggested, I now check for null and call it a day.