((me->flag&ME_SUBSURF) && me->subdiv)
In build_mesh_data(). This because meshes with subdiv==0 were calling a
MakeDisplist() for each redraw otherwise, disabling for example the
posemode "delay deform" feature. (bug #2700)
Daniel; it would help if you would add comments in the code, for example
to understand the difference between;
mesh_get_base_derived()
mesh_get_derived()
and how it relates to
build_mesh_data()
I realize most of the mess is in displist code... and confusing use
of features while editing, posemode, & render. Nevertheless, it's not
clear at first sight which parts of derivedmesh is design, and which
part reflects the hacks to make it work. :)