[Feature Request] Advanced Save/Reverse Merge

In a nutshell, this would be a kind of reverse advanced merge where you can select which elements of the active show file you want to push into another show file which is not open.

I have found the process of building a default show file with my personalized palettes, fixtures, magic sheets, macros etc. to be quite awkward.  As time goes on and I hit upon better solutions to various things, if I want to incorporate them into my default file currently I have to:

1) note down the identifying numbers of the elements I want to include
2) close the active show
3) open my default file
4) advanced merge in the elements I want to include from the closed show
5) close & save the default file
6) re-open the working show file

Instead, if there were an advanced save I could:

1) save as > advanced would open the advanced file dialog, where I itemize the elements I want to push into the default file.  Added efficiency from being able to reference the various tabs to pick out ID numbers.  Done and done without interrupting the current work.