We have a custom list within MOSS 2007 which sporadically closes the edit forms web part, despite the fact that the web parts property 'allow close' is unticked. The only way to make the form work again is to edit the page in SharePoint Designer and untick the option of 'web part closed', this then allows the form to function but at a seemingly random interval it will close itself again. There is quite a large user base accessing the site/list at anyone time, also note this has happened once on another list on another site collection. Has anyone else experienced this issue before or can offer any advice?