Most of the time it's working fine when this section is not repainted in ajax response. But there is a time when this section which is shown/collapsed is part of re-rendered areas. This time I have to remember if section was already collapsed or is expanded. So that if section was collapsed when ajax request went then while section is repainted, it should be collapsed only. Right now since the by default section is in "DISPLAY:BLOCK" mode, it will always be expanded when ajax response comes back.
some code will be more helpfull to give you advice.