Gui: fix screenshot

src/Mod/Part/Gui/SoBrepFaceSet.cpp

@@ -617,6 +617,15 @@ void SoBrepFaceSet::GLRender(SoGLRenderAction *action)
     // material override with transparncy won't work.
     mb.sendFirst(); 
 
+    if(SoShapeStyleElement::get(state)->getFlags() 
+            & (SoShapeStyleElement::TRANSP_TEXTURE|SoShapeStyleElement::TRANSP_MATERIAL))
+    {
+        // For some reason, there is an inconsistence in blending state between
+        // OpenGL and Coin, especially when doing offscreen rendering.
+        if(!glIsEnabled(GL_BLEND))
+            glEnable(GL_BLEND);
+    }
+
     // When setting transparency shouldGLRender() handles the rendering and returns false.
     // Therefore generatePrimitives() needs to be re-implemented to handle the materials
     // correctly.