when saving subcircuits across sessions, we need to save associated diode/transistor models

[pfalstad]

Load this circuit, save as circuit across sessions, reload. When accessing a menu, you get "model not found" error in console.

$ 1 0.000005 10.20027730826997 50 5 50 5e-11
34 hello 1 1.7143528192810002e-7 0 2.0000000000000084 0 1
d 416 368 528 352 2 hello
207 416 368 352 352 4 label1
207 528 352 608 352 4 label2