4 more Gmail Labs features you should be using

Several months ago, we took a look at some essential add-ons from Gmail Labs, Google’s workshop for experimental pre-release features. The most successful ones get formally added to Gmail. In fact, “Undo Send,” which was featured in our earlier roundup, was officially rolled out a few months ago. Others unceremoniously disappear, and still others come and go. But almost all add some productivity-enhancing functionality to your inbox.
We decided to see what was currently cookin