In Visual Studio 2010 Beta 1, you specifically selected if you were adding a Sequential Workflow or a Flowchart Workflow to your project. In Visual Studio 2010 Beta 2, everything is an activity. Instead of adding specific types of workflows to your project, you add an Activity.
In the Workflow Designer, you then drag either a Sequence activity or a Flowchart activity to the activity you just created. This might seem like a small difference, but this really improves the composability of workflows in WF4. Since workflows are no different than activities, we can compose a workflow of other workflows. It also allows us to execute custom activities in unit tests without needing to create a workflow that wraps that activity (see previous post).