Eclipse plugin development IDE question

I am trying to develop some simple Eclipse plugins. I am having some problems with my IDE when I try to add new extensions in my manifest. I created a sample plugin project. I selected MANIFEST.MF file and then opened it in editor. I switched to extensions tab and added new extension "org.eclipse.ui.command". When I right click on the newly added extensions, I get "New" -> "Generic". But tutorial says I would be seeing "org.eclipse.ui.command" specific options like "activeWhen", "category", "command" etc. Also when I try to click on "Show extension point description", I get an error. It looks similar to java development when javadoc is missing for the external jar. Should I need javadoc for the plugins too. Or Is there any specific preference which I am 开发者_高级运维missing? I have PDE plugin installed correctly. I am using Eclipse 3.5. If you have any solution, please share it.

You are not having the source bundles. Which package did you download? See here to know which one has the source bundles and which one doesn't.