diff --git a/src/OpenCSGRenderer.cc b/src/OpenCSGRenderer.cc
index 3c6f0b48..aa2d6bbb 100644
--- a/src/OpenCSGRenderer.cc
+++ b/src/OpenCSGRenderer.cc
@@ -90,7 +90,12 @@ void OpenCSGRenderer::renderCSGChain(CSGChain *chain, GLint *shaderinfo,
 				const Color4f &c = j_obj.color;
 				glPushMatrix();
 				glMultMatrixd(j_obj.matrix.data());
-				csgmode_e csgmode = j_obj.type == CSGTerm::TYPE_DIFFERENCE ? CSGMODE_DIFFERENCE : CSGMODE_NORMAL;
+				csgmode_e csgmode = csgmode_e(
+					(highlight ? 
+					 CSGMODE_HIGHLIGHT :
+					 (background ? CSGMODE_BACKGROUND : CSGMODE_NORMAL)) |
+					(j_obj.type == CSGTerm::TYPE_DIFFERENCE ? CSGMODE_DIFFERENCE : 0));
+
 				ColorMode colormode = COLORMODE_NONE;
 				if (background) {
 					if (j_obj.flag & CSGTerm::FLAG_HIGHLIGHT) {
@@ -99,11 +104,9 @@ void OpenCSGRenderer::renderCSGChain(CSGChain *chain, GLint *shaderinfo,
 					else {
 						colormode = COLORMODE_BACKGROUND;
 					}
-					csgmode = csgmode_e(csgmode + 10);
 				} else if (j_obj.type == CSGTerm::TYPE_DIFFERENCE) {
 					if (j_obj.flag & CSGTerm::FLAG_HIGHLIGHT) {
 						colormode = COLORMODE_HIGHLIGHT;
-						csgmode = csgmode_e(csgmode + 20);
 					}
 					else {
 						colormode = COLORMODE_CUTOUT;
@@ -111,7 +114,6 @@ void OpenCSGRenderer::renderCSGChain(CSGChain *chain, GLint *shaderinfo,
 				} else {
 					if (j_obj.flag & CSGTerm::FLAG_HIGHLIGHT) {
 						colormode = COLORMODE_HIGHLIGHT;
-						csgmode = csgmode_e(csgmode + 20);
 					 }
 					else {
 						colormode = COLORMODE_MATERIAL;
@@ -139,9 +141,12 @@ void OpenCSGRenderer::renderCSGChain(CSGChain *chain, GLint *shaderinfo,
 			
 			prim->geom = i_obj.geom;
 			prim->m = i_obj.matrix;
-			prim->csgmode = i_obj.type == CSGTerm::TYPE_DIFFERENCE ? CSGMODE_DIFFERENCE : CSGMODE_NORMAL;
-			if (highlight) prim->csgmode = csgmode_e(prim->csgmode + 20);
-			else if (background) prim->csgmode = csgmode_e(prim->csgmode + 10);
+			prim->csgmode = csgmode_e(
+				(highlight ? 
+				 CSGMODE_HIGHLIGHT :
+				 (background ? CSGMODE_BACKGROUND : CSGMODE_NORMAL)) |
+				(i_obj.type == CSGTerm::TYPE_DIFFERENCE ? CSGMODE_DIFFERENCE : 0));
+
 			primitives.push_back(prim);
 		}
 	}
diff --git a/src/ThrownTogetherRenderer.cc b/src/ThrownTogetherRenderer.cc
index 4b114041..dbdf527c 100644
--- a/src/ThrownTogetherRenderer.cc
+++ b/src/ThrownTogetherRenderer.cc
@@ -74,12 +74,15 @@ void ThrownTogetherRenderer::renderCSGChain(CSGChain *chain, bool highlight,
 		const Color4f &c = obj.color;
 		glPushMatrix();
 		glMultMatrixd(m.data());
-		csgmode_e csgmode  = obj.type == CSGTerm::TYPE_DIFFERENCE ? CSGMODE_DIFFERENCE : CSGMODE_NORMAL;
+		csgmode_e csgmode = csgmode_e(
+			(highlight ? 
+			 CSGMODE_HIGHLIGHT :
+			 (background ? CSGMODE_BACKGROUND : CSGMODE_NORMAL)) |
+			(obj.type == CSGTerm::TYPE_DIFFERENCE ? CSGMODE_DIFFERENCE : 0));
 		ColorMode colormode = COLORMODE_NONE;
 		ColorMode edge_colormode = COLORMODE_NONE;
 
 		if (highlight) {
-			csgmode = csgmode_e(csgmode + 20);
 			colormode = COLORMODE_HIGHLIGHT;
 			edge_colormode = COLORMODE_HIGHLIGHT_EDGES;
 		} else if (background) {
@@ -89,16 +92,11 @@ void ThrownTogetherRenderer::renderCSGChain(CSGChain *chain, bool highlight,
 			else {
 				colormode = COLORMODE_BACKGROUND;
 			}
-			csgmode = csgmode_e(csgmode + 10);
 			edge_colormode = COLORMODE_BACKGROUND_EDGES;
 		} else if (fberror) {
-			if (highlight) csgmode = csgmode_e(csgmode + 20);
-			else if (background) csgmode = csgmode_e(csgmode + 10);
-			else csgmode = csgmode_e(csgmode);
 		} else if (obj.type == CSGTerm::TYPE_DIFFERENCE) {
 			if (obj.flag & CSGTerm::FLAG_HIGHLIGHT) {
 				colormode = COLORMODE_HIGHLIGHT;
-				csgmode = csgmode_e(csgmode + 20);
 			}
 			else {
 				colormode = COLORMODE_CUTOUT;
@@ -107,7 +105,6 @@ void ThrownTogetherRenderer::renderCSGChain(CSGChain *chain, bool highlight,
 		} else {
 			if (obj.flag & CSGTerm::FLAG_HIGHLIGHT) {
 				colormode = COLORMODE_HIGHLIGHT;
-				csgmode = csgmode_e(csgmode + 20);
 			}
 			else {
 				colormode = COLORMODE_MATERIAL;
diff --git a/src/polyset.cc b/src/polyset.cc
index ad6b6e59..00ae963f 100644
--- a/src/polyset.cc
+++ b/src/polyset.cc
@@ -240,7 +240,7 @@ void PolySet::render_surface(Renderer::csgmode_e csgmode, const Transform3d &m,
 #endif /* ENABLE_OPENCSG */
 	if (this->dim == 2) {
 		// Render 2D objects 1mm thick, but differences slightly larger
-		double zbase = 1 + (csgmode & CSGMODE_DIFFERENCE_FLAG) * 0.1;
+		double zbase = 1 + ((csgmode & CSGMODE_DIFFERENCE_FLAG) ? 0.1 : 0);
 		glBegin(GL_TRIANGLES);
 
 		// Render top+bottom
@@ -369,7 +369,7 @@ void PolySet::render_edges(Renderer::csgmode_e csgmode) const
 		}
 		else {
 			// Render 2D objects 1mm thick, but differences slightly larger
-			double zbase = 1 + (csgmode & CSGMODE_DIFFERENCE_FLAG) * 0.1;
+			double zbase = 1 + ((csgmode & CSGMODE_DIFFERENCE_FLAG) ? 0.1 : 0);
 
 			BOOST_FOREACH(const Outline2d &o, polygon.outlines()) {
 				// Render top+bottom outlines
diff --git a/testdata/scad/2D/features/highlight-modifier-2d.scad b/testdata/scad/2D/features/highlight-modifier-2d.scad
new file mode 100644
index 00000000..7779fd69
--- /dev/null
+++ b/testdata/scad/2D/features/highlight-modifier-2d.scad
@@ -0,0 +1,10 @@
+difference() {
+  square(10, center=true);
+  #circle(3);
+}
+#if (true) square([11,12]);
+
+#translate([0,-12]) difference() {
+  square(10, center = true);
+  square(5, center = true);
+}
diff --git a/tests/regression/cgalpngtest/highlight-modifier-2d-expected.png b/tests/regression/cgalpngtest/highlight-modifier-2d-expected.png
new file mode 100644
index 00000000..9c2cedf1
Binary files /dev/null and b/tests/regression/cgalpngtest/highlight-modifier-2d-expected.png differ
diff --git a/tests/regression/dumptest/highlight-modifier-2d-expected.csg b/tests/regression/dumptest/highlight-modifier-2d-expected.csg
new file mode 100644
index 00000000..833d1ea4
--- /dev/null
+++ b/tests/regression/dumptest/highlight-modifier-2d-expected.csg
@@ -0,0 +1,15 @@
+group() {
+	difference() {
+		square(size = [10, 10], center = true);
+#		circle($fn = 0, $fa = 12, $fs = 2, r = 3);
+	}
+#	group() {
+		square(size = [11, 12], center = false);
+	}
+#	multmatrix([[1, 0, 0, 0], [0, 1, 0, -12], [0, 0, 1, 0], [0, 0, 0, 1]]) {
+		difference() {
+			square(size = [10, 10], center = true);
+			square(size = [5, 5], center = true);
+		}
+	}
+}
diff --git a/tests/regression/opencsgtest/difference-tests-expected.png b/tests/regression/opencsgtest/difference-tests-expected.png
index 69a4ac2e..4ffb06fd 100644
Binary files a/tests/regression/opencsgtest/difference-tests-expected.png and b/tests/regression/opencsgtest/difference-tests-expected.png differ
diff --git a/tests/regression/opencsgtest/highlight-modifier-2d-expected.png b/tests/regression/opencsgtest/highlight-modifier-2d-expected.png
new file mode 100644
index 00000000..24342191
Binary files /dev/null and b/tests/regression/opencsgtest/highlight-modifier-2d-expected.png differ
diff --git a/tests/regression/throwntogethertest/difference-tests-expected.png b/tests/regression/throwntogethertest/difference-tests-expected.png
index 4702fbff..fb1753c5 100644
Binary files a/tests/regression/throwntogethertest/difference-tests-expected.png and b/tests/regression/throwntogethertest/difference-tests-expected.png differ
diff --git a/tests/regression/throwntogethertest/highlight-modifier-2d-expected.png b/tests/regression/throwntogethertest/highlight-modifier-2d-expected.png
new file mode 100644
index 00000000..404d9e18
Binary files /dev/null and b/tests/regression/throwntogethertest/highlight-modifier-2d-expected.png differ