hiding cartoon/ribbon for any N-terminal part of an SSE causes a problem

[Elaine Meng]

This may be the same problem as #333, I'm not sure.

If you hide a ribbon segment such that it creates a new N-terminal end within any strand or helix, that new N-terminal end has a disjointed section. (This problem does not occur if you hide a ribbon segment such that it creates a new C-terminal end for an SSE.) For example,

open 3fx2
hide
rainbow
hide ~ strand cartoons
hide :2-5 cartoons (now there's an ugly square at :6)
hide :31-35 cartoons (similar problem)
cartoon
hide ~ helix cartoons
hide :13-21 cartoons (ick)
hide :145-148 cartoons (C-term truncation, looks fine)

[Elaine Meng]

Guess I don't understand why a new N-term is a problem when the N-term residue of the whole structure (3fx2) is in a strand and it looks fine.

[Conrad Huang]

Fixed in d91c2c5/chimerax.

Twist in ribbon are ignored at residue junction between secondary structure types (e.g., coil -> strand). Code was incorrectly ignoring twist even when two residues are of the same SS type when the first one is undisplayed.