Schema missing from eclipse plugin environment

I am getting this in my plugin perspective. I get a generic menu istead of specific items e.g. action, etc.

_{(source: sourceforge.net)}

My "Preferences / Plugin development / Target platform" looks like :

_{(source: sourceforge.net)}

When I go to edit it looks like :

Is this similar to this thread?

I just figured out what was the problem.
I was using an external target platform to run my plugins, where I had installed only the basic plugins. After I installed the sources org.eclipse.platform.source_2.1.0 and org.eclipse.platform.win32.source_2.1.0 also on the target platform, the manifest editor in the PDE was working normal again.

(to be adapted to your Eclipse version)

Also confirmed in this more recent thread:

Your target platform (and the default will be your own eclipse install) needs to have the source bundles (which provide the schema files used by these menus).

i.e. if I installed the runtime version, I will only get Generic in the menus but if I install the SDK version I will get real elements.

Thank you very much for the answer.
I "Add" source file to the platform (Preferences / Plugin development / Target platform) and got all menus!!