I won't want to have edit any working sets. I just want a way to, across all workspaces and projects, prevent .class files from ever showing in the Open Resource Dialog. Is there a way to do this?
I don't think that there is a solution. .class is still resource. Maybe You can use Open Type Dialog instead of Open Resource Dialog? If You're looking for Java sources of course.
One option is to filter derived resources. In the upper right corner of the 'Open Resource' dialog there is an arrow you can click to bring up a dropdown menu for filtering. Uncheck the 'Show Derived Resources' option, if it is checked.
If you still see '.class' files, they probably aren't being marked as derived. If they're by themselves in their own folder hierarchy you can fix this by right-clicking the root folder to edit folder properties, and check the 'Derived' checkbox. If they're mixed with your '.java' files...tough luck, you'd have to set the derived property on each '.class' file by hand.
As far as I can tell there's no way to mark class files as derived resources globally for the workspace, but I believe when you create a new Java project the 'bin' folder is marked as derived by default (if you use the default wizard settings)
Version 3.5 Open Resource dialog has a way turn "Show Derived Resources" on/off by a small dropdown menu at the top right hand corner. Turning it off will hide classes.
Or
you could type an expression on the "Select an item to open" text box such as : *.java