Layers mouse-following text was appear to be broken in some cases.
I found that causes were mostly for two reasons: was a bug in the way this code was used (by mistake, every time an action was started, was creating a new layer manager), the way it was updated (hinter component of our code may call update view just before adding layer, so nothing visible) and also I think an OCC related bug (that layers seems to not update if no scene (OCC context) changes are made).
So the whole code was moved up and down (in the idea that View component will include the OCC layer manager) so will not make possible cases like previous told. Also those layer structures are cleaned up every time you switch an action (making this code less prone to memory leaks) and will be less prone for API misuse. This refactor make it possible to discover that spline tools show mouse coordinate juxtaposed with hinter text, and this was also fixed.