问题
System:
Eclipse Standard/SDK
Version: Luna Release (4.4.0)
Build id: 20140612-0600
Aptana Plugin 3.6.0.
Problem:
In PHP-Explorer I see all my Projects in Workspace. In Project Explorer, I only see current open Projects.
So I check the setting in "Customize view".

The Setting is set to "show" all closed Project, but they don't.

Any Idea, how to got my closed Project shown there?
回答1:
I found the Problem.
A bit below the Checkbox "Closed projects" there is a Checkbox "PyDev closed projects". I've uncheck this Box and Projects are visible again.
Seems to be a Bug, cause this aren't Python Projects?!
I have createt an issue on aptana-bugtracker: https://jira.appcelerator.org/browse/APSTUD-8332
回答2:
The issue got resolved (Eclipse Mars) when i changed the "Top Level Elements" drop down value to "Projects". It was set to "Working Sets" previously.
来源:https://stackoverflow.com/questions/26295286/eclipse-shows-only-open-projects-in-project-explorer