Actually I had to change another line at function.php in order to get this working.
Just search for get_field_name(‘text’) and change the input type to TEXTAREA.
Hey ronr1999 thanks a lot!!!
I figure it out how to change the INPUT to a TEXTAREA. In the same file functions.php go to line 868:
CHANGE
<input name="<?php echo $this->get_field_name('text'); ?>" type="text" class="widefat" id="<?php echo $this->get_field_id('text'); ?>" value="<?php if( !empty($instance['text']) ): echo $instance['text']; endif; ?> " />
TO
<textarea name="<?php echo $this->get_field_name('text'); ?>" class="widefat" id="<?php echo $this->get_field_id('text'); ?>"><?php if( !empty($instance['text']) ): echo $instance['text']; endif; ?>
</textarea>
This should solve your problem!