How to make a copy of the existing form

Question

I am looking to make some modification to "Send To > Location" form.

Where can I find this form? And is it easy to make some modification and use it for a custom button?

Answer 1

You can find page in _layouts/copy.aspx in 14 hive \Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\LAYOUTS\, but it's strongly recommended not to modify the file itself. You can use reflector to get code of the form from SharePoint dll, but the code will be mess and hardly supportable.

So better solution is to create your own page and add move\copy logic there and create a custom action to add new option to action menu.