I was able to fix this error by removing the $instance argument from the function on line 101 of front-end-editor/php/fields/widget.php.
The new version looks like this:
function wrap( $content, $id_base = null ) {
// Only target text widgets
if ( 'title' == $this->field && 'text' != $id_base )
return $content;
if ( 'text' == $this->field )
$content = $this->placehold($content);
return FEE_Field_Base::wrap( $content, array() );
}
Hopefully this helps out a few people. No warranty or guarantees this won’t break something else, but so far, so good on several of my installs. For what it’s worth, the $instance parameter of the wrap function above doesn’t seem to be used in the function, so I’m not sure why it’s there anyway.