Mesh: Allow to measure distances with a mesh

src/Mod/Mesh/App/AppMesh.cpp

@@ -23,6 +23,7 @@
 #include "PreCompiled.h"
 
 #include <App/Application.h>
+#include <App/MeasureManager.h>
 #include <Base/Console.h>
 #include <Base/Interpreter.h>
 
@@ -73,6 +74,11 @@ PyMOD_INIT_FUNC(Mesh)
 
     Mesh::Extension3MFFactory::addProducer(new Mesh::GuiExtension3MFProducer);
 
+    // This registration is sufficient to allow to measure free distances with a mesh
+    App::MeasureManager::addMeasureHandler("Mesh", [](App::DocumentObject*, const char*) {
+        return App::MeasureElementType::INVALID;
+    });
+
     // init Type system
     Mesh::PropertyNormalList    ::init();
     Mesh::PropertyCurvatureList ::init();