SAMPLE: remember if collapsed

GUI/Model/Sample/CompoundItem.cpp

GUI/Model/Sample/CompoundItem.h

GUI/Model/Sample/CoreAndShellItem.cpp

GUI/Model/Sample/CoreAndShellItem.h

GUI/Model/Sample/LayerItem.cpp

GUI/Model/Sample/LayerItem.h

GUI/Model/Sample/MesocrystalItem.cpp

GUI/Model/Sample/MesocrystalItem.h

GUI/Model/Sample/ParticleItem.cpp

GUI/Model/Sample/ParticleItem.h

GUI/Model/Sample/ParticleLayoutItem.cpp

GUI/Model/Sample/ParticleLayoutItem.h

GUI/Model/Sample/SampleItem.cpp

GUI/Model/Sample/SampleItem.h

GUI/View/Instrument/InstrumentView.cpp

GUI/View/SampleDesigner/CompoundForm.cpp

GUI/View/SampleDesigner/CoreAndShellForm.cpp

GUI/View/SampleDesigner/InterferenceForm.cpp

GUI/View/SampleDesigner/LayerForm.cpp

GUI/View/SampleDesigner/MesocrystalForm.cpp