See bug description: https://bitbucket.org/Coin3D/coin/pull-requests/119/fix-sochildlist-auditing/diff Because of path based rendering (SoFCPathAnnotation) in mouse over highlight, this bug causes crash more frequently here comparing to upstream. All C++ calling of SoGroup::removeAllChildren() is replaced by Gui::coinRemoveAllChildren(), and python code is fixed by monkey patching SoGroup.removeAllChildren() in FreeCADGuiInit.py.