For everyone finding it frustrating that this feature isn't currently available - don't forget that this is a preview release. There are also several other features that are currently missing compared to the generally available client. Just because a feature isn't currently available, that doesn't mean it won't be added before general release. It's possible they are developing a slightly different (and potentially better) experience to the original one, which may explain why it's currently missing. If there's a feature missing that you find useful, either just wait, or if you can't live without it, just switch back to the original client. It's also worth using the feedback option in the top right to politely mention that you use the feature and so are hoping it gets added before general release. If several people do this, it gives MS some information regarding which features people are really hoping for.
