diff --git a/gerbview/CMakeLists.txt b/gerbview/CMakeLists.txt
index 8158de0f76..e919ac5e8c 100644
--- a/gerbview/CMakeLists.txt
+++ b/gerbview/CMakeLists.txt
@@ -34,6 +34,7 @@ set( GERBVIEW_SRCS
     class_gerbview_layer_widget.cpp
     class_gbr_layer_box_selector.cpp
     class_X2_gerber_attributes.cpp
+    clear_gbr_drawlayers.cpp
     controle.cpp
     dcode.cpp
     draw_gerber_screen.cpp
@@ -44,7 +45,7 @@ set( GERBVIEW_SRCS
     gerbview_config.cpp
     gerbview_frame.cpp
     hotkeys.cpp
-    init_gbr_drawlayers.cpp
+    clear_gbr_drawlayers.cpp
     locate.cpp
     menubar.cpp
     onleftclick.cpp
diff --git a/gerbview/class_aperture_macro.cpp b/gerbview/class_aperture_macro.cpp
index 7ff3e2550b..e884d5c922 100644
--- a/gerbview/class_aperture_macro.cpp
+++ b/gerbview/class_aperture_macro.cpp
@@ -91,7 +91,7 @@ bool AM_PRIMITIVE::mapExposure( GERBER_DRAW_ITEM* aParent )
             break;
 
         default:
-        case 1:     // exposure always OON
+        case 1:     // exposure always ON
             exposure = true;
             break;
 
diff --git a/gerbview/init_gbr_drawlayers.cpp b/gerbview/clear_gbr_drawlayers.cpp
similarity index 93%
rename from gerbview/init_gbr_drawlayers.cpp
rename to gerbview/clear_gbr_drawlayers.cpp
index be33329f7e..139790ea47 100644
--- a/gerbview/init_gbr_drawlayers.cpp
+++ b/gerbview/clear_gbr_drawlayers.cpp
@@ -2,7 +2,7 @@
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
  * Copyright (C) 2013 Jean-Pierre Charras, jp.charras at wanadoo.fr
- * Copyright (C) 1992-2013 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 1992-2016 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -23,7 +23,8 @@
  */
 
 /**
- * @file init_gbr_drawlayers.cpp
+ * @file clear_gbr_drawlayers.cpp
+ * @brief erase a given or all draw layers, an free memory relative to the cleared layer(s)
  */
 
 #include <fctsys.h>
diff --git a/gerbview/gerber_test_files/aperture_macro_with_negative_object.gbr b/gerbview/gerber_test_files/aperture_macro_with_negative_object.gbr
new file mode 100644
index 0000000000..bd430fba10
--- /dev/null
+++ b/gerbview/gerber_test_files/aperture_macro_with_negative_object.gbr
@@ -0,0 +1,70 @@
+%TF.GerberVersion,J4*%
+%TF.Part,Single*%
+%TF.FileFunction,Other,BugReportExample*%
+
+%FSLAX26Y26*%
+%MOIN*%
+
+%LPD*%
+
+%SRX1Y1I0J0*%
+
+
+G04 ===================================================*
+G04 Aperture Macros*
+G04 AMHALFCIRCLE draws a half circle by drawing a full circle and then
+G04  a rectangular negative object overlapping the other half circle
+G04 ===================================================*
+%AMHALFCIRCLE*
+1,1,1,0,0,0,0*
+2,0,1,0,0,-.5,0,0*%
+
+
+
+
+G04 ===================================================*
+G04 Aperture Definitions*
+G04 ===================================================*
+%ADD10HALFCIRCLE*%
+%ADD20HALFCIRCLE*%
+%ADD30HALFCIRCLE*%
+
+
+
+G04 ===================================================*
+G04 Program*
+G04 ===================================================*
+
+G01*
+
+G04 ---------------------------------------------------*
+G04 The following code should produce similar outputs. *
+G04 That is, 2 half circles side by side.  However,    *
+G04 only the flashes done with D10 are correct. With   *
+G04 the D20, the second aperture flash erases the first*
+G04 which should not happen according to the gerber    *
+G04 file format specifications.  The only difference   *
+G04 between the D10 and D20 flashes are the Y coords.  *
+G04 and the order of the flash statements.             *
+G04 Note: D30 shows one flash (one aperture macro).    *
+G04                                                    *
+G04 See section 4.12.2 of the Ucamco Gerber Format     *
+G04 Specification document for more details on aperture*
+G04 macro exposure modifiers.                          *
+G04 ---------------------------------------------------*
+
+
+D10*
+X500000Y2000000D03*
+X0Y2000000D03*
+
+
+D20*
+X0Y0D03*
+X500000Y0D03*
+
+D30*
+X1500000Y1000000D03*
+
+
+M02*
\ No newline at end of file