Cache a weak pointer to state before operator so to save on re-executing
Cache a weak pointer to state before operator so to save on re-executing

mathturtle/tomviz,cjh1/tomviz,cryos/tomviz,thewtex/tomviz,cryos/tomviz,OpenChemistry/tomviz,cjh1/tomviz,cjh1/tomviz,OpenChemistry/tomviz,cryos/tomviz,mathturtle/tomviz,OpenChemistry/tomviz,thewtex/tomviz,OpenChemistry/tomviz,thewtex/tomviz,mathturtle/tomviz