The lastest STS is 2.5.2, freshly released yesterday! Hopefully it will fix some of the issues you're seeing.
@magott: Because we're no longer bundling the Spring Integration jars with STS, you'll have to add the integration-twitter jar to your project classpath whenever you want to use it. You'll also have to ensure that STS is loading the XML schemas from the project classpath. You can do this by opening up the STS Preferences->Spring->Beans Support->Namespaces and checking the box that says "Load NamespaceHandlers and XSDs from project classpath". You'll then have to reopen any XML files to pick up the change. Hope that helps!
Leo Dos Santos
Committer, SpringSource Tool Suite