As in my question title: I got several update panels in a page, and each of them contains a "Add Extra" button. I also added a modal popup extender, and a popup panel.
My question is how can I reuse this ModalPopupExtender for all these "Add Extra" buttons click,
it only has one TargetControlId attribute.
In addition, because I put this ModalPopupExtender outside any update panel, so I got an error when I try to open this page:
" Error:An extender can't be in a different UpdatePanel than the control it extends. "
How can I get rid of this problem, and why an extender can't be in a different UpdatePanel than the control it extends?