Insert Glyph to Background.py & Smart Components

[Mark2Mark]

Lovely script, thanks a lot for it.

In Glyphs 3, when unchecking "As Component" and inserting a smart glyph (with smart layers), it adds the corresponding sub-layers, but unfortunately alwaus only the ones from the last master.

e.g.

Currently happening:

┌─Source Glyph─┐        ┌─Target Glyph─┐
│              │        │              │
│ REGULAR      │        │ REGULAR      │
│              │        │              │
│   narrow     │      ┌▶│   narrow     │
│              │    ┌─┘ │              │
│   wide       │  ┌─┘ ┌▶│   wide       │
│              │┌─┘ ┌─┘ │              │
│ BLACK       ┌┼┘ ┌─┘   │ BLACK        │
│           ┌─┘│┌─┘     │              │
│   narrow ─┘ ┌┼┘ ─────▶│   narrow     │
│           ┌─┘│        │              │
│   wide   ─┘  │  ─────▶│   wide       │
└──────────────┘        └──────────────┘
                                        
As opposed to the expected:
                                        
┌─Source Glyph─┐        ┌─Target Glyph─┐
│              │        │              │
│ REGULAR      │        │ REGULAR      │
│              │        │              │
│   narrow     │───────▶│   narrow     │
│              │        │              │
│   wide       │───────▶│   wide       │
│              │        │              │
│ BLACK        │        │ BLACK        │
│              │        │              │
│   narrow     │───────▶│   narrow     │
│              │        │              │
│   wide       │───────▶│   wide       │
└──────────────┘        └──────────────┘