problem when using more than 2 forms with ckeditor

I'm trying to use ckeditor with more than 2 form like

<form id="form1">
  <textarea class="ckeditor" name="t1"></textarea>
</form>
<form id="form2">
  <textarea class="ckeditor" name="t2"></textarea>
</form>
<form id="form3">
  <textarea class="ckeditor" name="t3"></textarea>
</form>

then there are problems.
1st editor works fine,
but 2nd one won't follow the settings like config.uiColor
and 3rd one even disappeared!

can anyone help me solve this problem?