Remember PluginFest?
It's been a while since it was held. The Eclipse PluginFest was a really cool event organized by Ian Skerrett and hosted by the folks at Symbian in London. It was part marketing event and part engineering event intended to show how off the promise of Eclipse as a platform by doing some interoperability testing between the different products, focusing at the time on the embedded/mobile market. For the most part, it was a success, especially for tools up the stack like analysis and modeling tools.
But one thing that was clear then and is still true today is that plug-ins from platform providers, generally vendors that provide tools for building applications and customizations for their operating systems, don't mix. In fact most of them assume that you are not building for other platforms and many of them have their own version of the Eclipse platform.