In at least SDL Tridion 2011, Content Manager Explorer and Template Builder run against the current, even if minor, version of a template. Publishing will use the last major, checked-in, template version.

**For Template Building Blocks (TBBs):**

How do the following [publishing contexts][1]* affect TBB versions?

 - Template Builder
 - CME Preview
 - Session Preview
 - Publish

*This would mainly be for DWT TBBS and C# TBB fragments. I'm not sure how we'd create a minor version of a TBB that's part of an assembly (it that possible with `TcmUploadAssembly`?).*

**For Session Preview**

Also, which version of a template should Session Preview use?

**Background**: in older versions of Tridion, we had to *check in* (at least) legacy templates to see changes in CME Preview (update, Save & Close, then see changes). Now we can simply Save then check, but I'm not sure for XPM... yet (update follows). :-)

**Update:** Changing markup in a DWT without publishing *does* show in Session Preview. If viewing as the user that made the DWT edit, I see the latest template, even if it's a minor version. However, viewing as another user, I only see the last major version.

*In other words, if viewing the page as the same user, we can edit a DWT, save, and then immediately see the changes in Experience Manager without checking in.* Feel free to clarify or add more; I'll also this as a community answer.

  [1]: http://stackoverflow.com/a/14642317/395495