diff --git a/src/Mod/Sketcher/Gui/SoDatumLabel.cpp b/src/Mod/Sketcher/Gui/SoDatumLabel.cpp
index 36b8ed6a2f..7f3d1e260e 100644
--- a/src/Mod/Sketcher/Gui/SoDatumLabel.cpp
+++ b/src/Mod/Sketcher/Gui/SoDatumLabel.cpp
@@ -834,12 +834,12 @@ void SoDatumLabel::GLRender(SoGLRenderAction * action)
         const SbViewportRegion & vpr = SoViewportRegionElement::get(state);
 
         SoGetMatrixAction * getmatrixaction = new SoGetMatrixAction(vpr);
-        getmatrixaction->apply(this);
+        getmatrixaction->apply(action);
 
         SbMatrix transform = getmatrixaction->getMatrix();
         transform.multVecMatrix(surfNorm, surfNorm);
 
-        bool flip = surfNorm.dot(z) > 0;
+        bool flip = surfNorm.dot(z) > FLT_EPSILON;
 
         glDisable(GL_DEPTH_TEST);
         glEnable(GL_TEXTURE_2D); // Enable Textures