It seems in the 2.14.2 version of QGIS the ability to copy the WKT from the geometry of a temporary scratch layer has been removed.
Previously you could create, for example, a new polygon feature in a temporary scratch layer and use the identify tool to reveal the attributes of the temporary feature. From there, you could right-click the feature and 'copy' the feature attributes, which contained the WKT of the geometry of the feature.
Now the identify window and the attribute table are both blank where they used to show the attributes of the feature.
That was super handy for spatial queries using ad-hoc geometries...