Create calculated metrics by selecting items inside a Workspace - Status changed to: New

[#1]

Often, one realizes that a calculation would be helpful while constructing a workspace.  It would be helpful to be able to select items already placed in the workspace and add in operators to create a calculated metric on the fly.-- as opposed to having to find and place those same elements inside the calculated metric creation popup.

We can select something and automatically create a segment. This would be similar to that experience.