[Core] Disable toggling visibility for objects

- VarSet
- Spreadsheet
- FEM objects

src/Mod/Fem/Gui/ViewProviderAnalysis.cpp

@@ -101,6 +101,7 @@ PROPERTY_SOURCE(FemGui::ViewProviderFemAnalysis, Gui::ViewProviderDocumentObject
 
 ViewProviderFemAnalysis::ViewProviderFemAnalysis()
 {
+    setToggleVisibility(ToggleVisibilityMode::NoToggleVisibility);
     sPixmap = "FEM_Analysis";
 }