Quick filter by label
Currently to filter by a label you either have to type in the label such as "@mylabel" and hit enter, or you have to click the "@" to see a list of labels and click on one.
It would be great if the screen always showed a list of all the labels and I could click on it to filter my current screen at any time. So, like you have the list of projects on the left, you could have a list of colored labels on the right, or under the labels on the left.
So this would be similar to the Gmail concept of labels, where they list the labels down the left side.
You would also need a way to "unfilter" (all labels).