As far as I’ve known if the ClientID of a server control looked someting like this:
Then the name sent on postback (which identified the control on the server side) was:
But since some time the _ to $ conversion is not true any more. Instead the _ signs are randomly replaced by dollar signs. Recently the name sent back on postback is:
This change screwed up quite a lot of client side manual __doPostback() codes I’ve written – most of the making these invokes due to JQuery addons.