diff --git a/gui/shaders/canvas-pipeline.frag b/gui/shaders/canvas-pipeline.frag
index 9fdb9ff4f..7bc229eac 100644
--- a/gui/shaders/canvas-pipeline.frag
+++ b/gui/shaders/canvas-pipeline.frag
@@ -1,7 +1,5 @@
 // -*-C++-*-
-#version 330
-
-/*** Enum constans ************************************/
+#version 330 core
 
 #define PAINT_TYPE_COLOR            0x1B00
 #define PAINT_TYPE_LINEAR_GRADIENT  0x1B01
@@ -14,40 +12,19 @@
 #define DRAW_MODE_PATH              0
 #define DRAW_MODE_IMAGE             1
 
-/*** Interpolated *************************************/
-
 in vec2 texImageCoord;
 in vec2 paintCoord;
 
-/*** Input ********************************************/
-
-// Basic rendering Mode
 uniform int drawMode;
-// Image
 uniform sampler2D imageSampler;
 uniform int imageMode;
-// Paint
 uniform int paintType;
 uniform vec4 paintColor;
 uniform vec2 paintParams[3];
-// Gradient
 uniform sampler2D rampSampler;
-// Pattern
 uniform sampler2D patternSampler;
-// Color transform
 uniform vec4 scaleFactorBias[2];
 
-/*** Output *******************************************/
-
-//out vec4 fragColor;
-
-/*** Built-in variables for shMain *******************************************/
-
-vec4 sh_Color;
-
-/*** Functions ****************************************/
-
-// 9.3.1 Linear Gradients
 float linearGradient(vec2 fragCoord, vec2 p0, vec2 p1){
 
     float x  = fragCoord.x;
@@ -64,7 +41,6 @@ float linearGradient(vec2 fragCoord, vec2 p0, vec2 p1){
      /  ( dx*dx + dy*dy );
 }
 
-// 9.3.2 Radial Gradients
 float radialGradient(vec2 fragCoord, vec2 centerCoord, vec2 focalCoord, float r){
 
     float x   = fragCoord.x;
@@ -83,16 +59,10 @@ float radialGradient(vec2 fragCoord, vec2 centerCoord, vec2 focalCoord, float r)
      /  ( r*r - (dfx*dfx + dfy*dfy) );
 }
 
-// User defined shader
-void shMain(void);
-
-/*** Main thread  *************************************/
-
 void main()
 {
     vec4 col;
 
-    /* Stage 6: Paint Generation */
     switch(paintType){
     case PAINT_TYPE_LINEAR_GRADIENT:
         {
@@ -125,15 +95,10 @@ void main()
         break;
     }
 
-    /* Stage 7: Image Interpolation */
     if(drawMode == DRAW_MODE_IMAGE) {
         col = texture(imageSampler, texImageCoord)
                   * (imageMode == DRAW_IMAGE_MULTIPLY ? col : vec4(1.0, 1.0, 1.0, 1.0));
     }
 
-    /* Stage 8: Color Transformation, Blending, and Antialiasing */
-    sh_Color = col * scaleFactorBias[0] + scaleFactorBias[1] ;
-
-    /* Extended Stage: User defined shader that affects gl_FragColor */
-    shMain();
+    gl_FragColor = col * scaleFactorBias[0] + scaleFactorBias[1];
 }
diff --git a/gui/shaders/canvas-pipeline.vert b/gui/shaders/canvas-pipeline.vert
index 4ee82bee2..d8293622b 100644
--- a/gui/shaders/canvas-pipeline.vert
+++ b/gui/shaders/canvas-pipeline.vert
@@ -1,39 +1,16 @@
 // -*-C++-*-
-#version 330
+#version 330 core
 
-/*** Input *******************/
 in vec2 pos;
 in vec2 textureUV;
-uniform mat4 sh_View;
-uniform mat4 sh_Model;
-uniform mat4 sh_Ortho;
 uniform mat3 paintInverted;
 
-/*** Output ******************/
 out vec2 texImageCoord;
 out vec2 paintCoord;
 
-/*** Grobal variables ********************/
-vec4 sh_Vertex;
-
-/*** Functions ****************************************/
-
-// User defined shader
-void shMain(void);
-
-/*** Main thread  **************************************************/
-void main() {
-
-    /* Stage 3: Transformation */
-    sh_Vertex = vec4(pos, 0, 1);
-
-    /* Extended Stage: User defined shader that affects gl_Position */
-    shMain();
-
-    /* 2D pos in texture space */
+void main()
+{
+//  gl_Position = vec4(pos, 0, 1);
     texImageCoord = textureUV;
-
-    /* 2D pos in paint space (Back to paint space) */
     paintCoord = (paintInverted * vec3(pos, 1)).xy;
-
 }
diff --git a/gui/shaders/canvas-user-default.frag b/gui/shaders/canvas-user-default.frag
deleted file mode 100644
index 84eb554c9..000000000
--- a/gui/shaders/canvas-user-default.frag
+++ /dev/null
@@ -1,6 +0,0 @@
-// -*-C++-*-
-void shMain() {
-
-    gl_FragColor = sh_Color;
-
-}
diff --git a/gui/shaders/canvas-user-default.vert b/gui/shaders/canvas-user-default.vert
deleted file mode 100644
index 03c2d6d98..000000000
--- a/gui/shaders/canvas-user-default.vert
+++ /dev/null
@@ -1,6 +0,0 @@
-// -*-C++-*-
-void shMain() {
-
-    gl_Position = sh_Ortho * sh_View * sh_Model * sh_Vertex;
-
-}