setting (default: on
, except in PyMOL 220.127.116.11 - 18.104.22.168
) controls whether PyMOL does case sensitive matching of atomic identifiers and selection operators in the selection language. Most notably, it affects whether chain identifiers are matched case sensitive, which becomes relevant when using upper and lower case chain identifiers in a structure with more than 26 chains.
Load 1a00 which has chains A, B, C, D
PyMOL>fetch 1a00, async=0
1) case insensitive selection language (default for PyMOL <= 1.7.6 and >= 22.214.171.124)