FEM: allow to make a mesh from shape without an analysis

src/Mod/Fem/FemCommands.py

@@ -55,7 +55,7 @@ def IsActive(self):
             elif self.is_active == 'with_results':
                 active = FemGui.getActiveAnalysis() is not None and self.active_analysis_in_active_doc() and self.results_present()
             elif self.is_active == 'with_part_feature':
-                active = FemGui.getActiveAnalysis() is not None and self.active_analysis_in_active_doc() and self.part_feature_selected()
+                active = FreeCADGui.ActiveDocument is not None and self.part_feature_selected()
             return active
 
         def results_present(self):