I have two buttons in my page. The 'select image' button and a 'start upload' button.

The 'start upload' button is disabled by default, but should be enabled when I click the 'select image' button.

 

Just can't get it to work, because the events OnClientClick AND OnClick doesn't seem to be working on the 'select image' button.

 

(it's a ManualStartUpload with a custom InsertButtonID)