[news.eclipse.tools] how to auto-load my plugin if project contains my p

["Dorren Chen" <dorrenchen@xxxxxxxxx>]

I'm developing a plugin that captures some info about the project and save
them as project persistent property. When eclipse starts and project with my
properties loads, my plugin is not activated automatically, I have to do
some action that use plug-in class, then plug-in will work.

how to automatically activate my plug-in if project contains my persistent
property?  Thanks.