Comment 3 for bug 1098563

It should be possible to know which module instances are exact copy of the part from the original library and which were changed. Typically none or few ones are changed. When you add a new module on the board, it would be nice to copy it from other unchanged module copy from the same board (if found).

OrCAD copies the parts and modules from libraries to the design cache and uses instances of these master symbols. When any part/module is being altered, it creates a new master symbol with slightly different name in the design cache.

When you edit some board later, it is possible, that libraries were slightly changed and the new module is not similar with the same ones used on the board.

The same problem comes with eeschema. The part symbols in libraries are sometimes changed (enhanced). If you need to move pins, all older schematics that used the part can become "broken" and need some editing. Opening several years old design can be a nightmare in this case.

When I pass my design to a colleague, it's a problem how to synchronize our libraries, since we both are adding new components. When all the used parts would be included in a design cache (eeschema and pcbnew), these problems would be gone.