I'm using update panels within a SharePoint 2010 form - I know update panels aren't the best thing to be using in the first place, but time is a issue on our project - and after a user triggers a second update the rich text box is becoming read only. The control doesn't allow me to enter text when I click on it and it doesn't display the cursor. I can get around it by selecting a item from the toolbar, but I'm not sure why that works.
In the past, I had issues with the update panel leaving HTML tags after a single update. I've resolved this issue by following this page. Any thoughts?