The trick is to open the "Navigator" view, right click on the folder to be ignored, and check the "Derived" property. This option informs Eclipse that this folder consists of generated resources that should not be directly edited. Once this is done, the "Open Resource..." view will only show matches that would be relevant to the developer.
Eclipse Resource Filtering
Today i found a solution to the single most irritating thing with Eclipse. To not be able to filter away resources from the Open Resource dialog. This was of course possible but I've never even thought about it until a coworker passed me this link. I quote: