The edit entry field for FaceGen hex strings is still not long enough to paste the full string into. It seems that the alt method I happened upon (enter directly into the field, instead of a dialog box) is unavailable (or I can't figure it out anymore).
If FONV attempts to load this incomplete FaceGen hex string, the game will crash.
Here is a full FaceGen face geometry string (the first one, symmetrical face geometry). Spoiler tags since they're super-long.
Spoiler 57 33 1C 3D 00 79 DA BE E8 B2 17 40 02 AD 96 BF 00 EE 69 3C 56 D4 42 BF 3B BE C6 3F 8C CF 8C BE A4 CF 29 3F F6 23 C3 3E 88 3D 9E BE 5A C5 21 40 3C D5 9E 3F 10 99 00 BF 52 D4 6D BE DB 97 50 C0 BC 6D E6 3F 00 C9 35 BE 17 9C A7 40 FE 5E F8 BE 5E 43 C7 BF 4E BE 9F 40 3D 63 93 C0 00 88 E3 BD E4 4F AD C0 E6 9A CC BF 72 0D 29 C0 B2 5B 00 40 60 26 09 C0 37 9B 16 40 B8 E3 18 BD 0C 9A ED 3F 86 2A 3E 40 25 D4 84 C0 2A F0 BF 3F 4C D1 F9 BF D9 43 6A C0 A0 89 EC BF 37 EA A1 40 18 95 35 C0 16 73 02 40 64 A1 0F 3F CC 82 24 40 98 F5 56 3F 5C ED FE 3F B2 19 13 40 B2 B3 A5 BF C8 D4 A0 40 72 9E 8E C0 9A 9D F4 40
Here is all that the FNVEdit will enter.
Spoiler 57 33 1C 3D 00 79 DA BE E8 B2 17 40 02 AD 96 BF 00 EE 69 3C 56 D4 42 BF 3B BE C6 3F 8C CF 8C BE A4 CF 29 3F F6 23 C3 3E 88 3D 9E BE 5A C5 21 40 3C D5 9E 3F 10 99 00 BF 52 D4 6D BE DB 97 50 C0 BC 6D E6 3F 00 C9 35 BE 17 9C A7 40 FE 5E F8 BE 5E 43 C7 BF 4E
As you can see, the second is incomplete, not even half of it. I cannot paste the omitted parts onto the end, the field is just not long enough. It's not even long enough for the Asymmetric geometry line, which is shorter than the symmetric geometry and texture lines.
EDIT: It seems the message about double-clicking on fields got considered (concerning FormList accidents), but the fact that the FaceGen hex code fields are too short did not. I can double-click to alter FaceGen strings in FO3Edit (older version) but I cannot in FNVEdit. The double-click on the field was long enough to enter FaceGen strings. Fixing one but not the other essentially makes it impossible to manipulate FaceGen data in FNVEdit.