Why does Eclipse load all plugins in a workspace?

Question

I'm using Eclipse 3.6 for developing Eclipse plug-in. In the same workspace, I have 2 Plug-in projects： projA and projB. No mater which project was run, both two projects will be loaded in the new Eclipse instance. If I only want to load projA, I have to close projB, why? I run the project like this: right click the project and "Run as--- Eclipse Application".

Answer 1

Have you defined the target platfom?

You can also edit your Run Configuration and choose the plugins to launch with.

Answer 2

The way you debug your project will start a new instance of Eclipse with all existing plugins installed(in your case,both project A and B are installed).This is typically called self-hosting in PDE.
If project A has no dependent package,just close other projects.