Sketcher: Fix ticket #4399
Sketcher: Fix ticket #4399

The reason for this behaviour is that root point (origin) and axes are not treated as fixed geometry. Every external geometry has negative ID which is at most GeoEnum::RefExt defined as -3 in the file src/Mod/Sketcher/App/SketchObject.cpp. Ids of root point and axes are also defined in this file with id -1 for root point and horizontal axis, and -2 for vertical axis. To fix the problem, GeoEnum::RefExt id was replaced by root point id in the condition checking for the largest id of fixed geometry.
Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master