id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	blockedby	blocking	notify_on_close	platform	project
791	Cannot change b-factors or occupancies	Tristan Croll	eric	"
{{{
m = session.models.list()[0]
a = m.atoms[0]
a.bfactor
> 1.0

a.bfactor = 0.5
a.bfactor
> 1.0
}}}


I believe the culprit here is in CoordSet.cpp, in CoordSet::set_bfactor and ::set_occupancy - where you have 

{{{
..._map.insert(...)
}}}
 
you want:

{{{
..._map.insert_or_assign(...)
}}}
 
From the documentation for std::unordered_map::insert:

  Inserts element(s) into the container, if the container doesn't already contain an element with an equivalent key. 

"	defect	closed	major		Core		fixed						all	ChimeraX