If it were me, I think I'd try to use Rules and VBO. I haven't tried it myself, but I'm pretty sure the functionality is there without a custom module.
Rules allows you to create a condition (Save a node, or maybe even Save a node as sticky) and then fire an action, which using Views Bulk Operations (VBO) can find all other sticky nodes and turn them non-sticky.
Hope that helps,
Joel
From: support-bounces@drupal.org [mailto:support-bounces@drupal.org] On Behalf Of Pooya Sent: Thursday, May 05, 2011 6:29 AM To: support@drupal.org Subject: [support] Use only one 'Sticky at top of lists'
Do you guys know any module which makes drupal to allow only one node with the option 'Sticky at top of lists'? My client needs to have only one sticky node, if there is already another node with sticky option selected when adding new node, previous nodes 'sticky' option should become disabled.
If there's no such module or easy way, I've got to make one which takes longer.
Thanks in advanced :)