I have a DataObjectDecorator for the File class that needs to add and remove a few fields from the file popup. While updateCMSFields() is called, I seem to be unable to modify the fields in the popup. I have the DataObjectManager module installed (and uploadify, but that's not affecting this), and the file popup is clearly a DataObjectManager_Popup (DOM_P) object.
How can I add/remove fields from a DOM_P? A method for updateCMSFields() to detect whether it's deling with a DOM_P GUI would be handy too.
It turned out that an if statement that was checking if the file had a valid ID was stopping the code from running. It's all solved now, and there's nothing special about customising DataObjectManager popup GUIs.
I find it odd that the File object's ID field was set to zero when updateCMSFields() was called, as these were existing files with corresponding database entries.