diff --git a/resources/shaders/110/gouraud.fs b/resources/shaders/110/gouraud.fs
index 0742f6cc88..cf3163fa37 100644
--- a/resources/shaders/110/gouraud.fs
+++ b/resources/shaders/110/gouraud.fs
@@ -26,8 +26,6 @@ struct SlopeDetection
 uniform vec4 uniform_color;
 uniform SlopeDetection slope;
 
-uniform bool offset_depth_buffer;
-
 #ifdef ENABLE_ENVIRONMENT_MAP
     uniform sampler2D environment_tex;
     uniform bool use_environment_tex;
@@ -78,9 +76,4 @@ void main()
     else
 #endif
         gl_FragColor = vec4(vec3(intensity.y) + color * intensity.x, alpha);
-		
-    // In the support painting gizmo and the seam painting gizmo are painted triangles rendered over the already
-    // rendered object. To resolved z-fighting between previously rendered object and painted triangles, values
-    // inside the depth buffer are offset by small epsilon for painted triangles inside those gizmos.
-    gl_FragDepth = gl_FragCoord.z - (offset_depth_buffer ? EPSILON : 0.0);
 }
diff --git a/resources/shaders/110/mm_contour.fs b/resources/shaders/110/mm_contour.fs
index 14477a59e6..ab656998df 100644
--- a/resources/shaders/110/mm_contour.fs
+++ b/resources/shaders/110/mm_contour.fs
@@ -1,13 +1,8 @@
 #version 110
 
-const float EPSILON = 0.0001;
-
 uniform vec4 uniform_color;
 
 void main()
 {
     gl_FragColor = uniform_color;
-    // Values inside depth buffer for fragments of the contour of a selected area are offset
-    // by small epsilon to solve z-fighting between painted triangles and contour lines.
-    gl_FragDepth = gl_FragCoord.z - EPSILON;
 }
diff --git a/resources/shaders/110/mm_contour.vs b/resources/shaders/110/mm_contour.vs
index d9063f0c70..b37394b619 100644
--- a/resources/shaders/110/mm_contour.vs
+++ b/resources/shaders/110/mm_contour.vs
@@ -2,10 +2,14 @@
 
 uniform mat4 view_model_matrix;
 uniform mat4 projection_matrix;
+uniform float offset;
 
 attribute vec3 v_position;
 
 void main()
 {
-    gl_Position = projection_matrix * view_model_matrix * vec4(v_position, 1.0);
+    // Add small epsilon to z to solve z-fighting between painted triangles and contour lines.
+	vec4 clip_position = projection_matrix * view_model_matrix * vec4(v_position, 1.0);
+	clip_position.z -= offset * abs(clip_position.w);
+    gl_Position = clip_position;
 }
diff --git a/resources/shaders/140/gouraud.fs b/resources/shaders/140/gouraud.fs
index beb3a947bb..273779ca84 100644
--- a/resources/shaders/140/gouraud.fs
+++ b/resources/shaders/140/gouraud.fs
@@ -26,8 +26,6 @@ struct SlopeDetection
 uniform vec4 uniform_color;
 uniform SlopeDetection slope;
 
-uniform bool offset_depth_buffer;
-
 #ifdef ENABLE_ENVIRONMENT_MAP
     uniform sampler2D environment_tex;
     uniform bool use_environment_tex;
@@ -78,9 +76,4 @@ void main()
     else
 #endif
         gl_FragColor = vec4(vec3(intensity.y) + color * intensity.x, alpha);
-		
-    // In the support painting gizmo and the seam painting gizmo are painted triangles rendered over the already
-    // rendered object. To resolved z-fighting between previously rendered object and painted triangles, values
-    // inside the depth buffer are offset by small epsilon for painted triangles inside those gizmos.
-    gl_FragDepth = gl_FragCoord.z - (offset_depth_buffer ? EPSILON : 0.0);
 }
diff --git a/resources/shaders/140/mm_contour.fs b/resources/shaders/140/mm_contour.fs
index 3681d76c18..e74124dcae 100644
--- a/resources/shaders/140/mm_contour.fs
+++ b/resources/shaders/140/mm_contour.fs
@@ -1,13 +1,8 @@
 #version 140
 
-const float EPSILON = 0.0001;
-
 uniform vec4 uniform_color;
 
 void main()
 {
     gl_FragColor = uniform_color;
-    // Values inside depth buffer for fragments of the contour of a selected area are offset
-    // by small epsilon to solve z-fighting between painted triangles and contour lines.
-    gl_FragDepth = gl_FragCoord.z - EPSILON;
 }
diff --git a/resources/shaders/140/mm_contour.vs b/resources/shaders/140/mm_contour.vs
index 7042671de2..679291ba6d 100644
--- a/resources/shaders/140/mm_contour.vs
+++ b/resources/shaders/140/mm_contour.vs
@@ -2,10 +2,14 @@
 
 uniform mat4 view_model_matrix;
 uniform mat4 projection_matrix;
+uniform float offset;
 
 in vec3 v_position;
 
 void main()
 {
-    gl_Position = projection_matrix * view_model_matrix * vec4(v_position, 1.0);
+    // Add small epsilon to z to solve z-fighting between painted triangles and contour lines.
+	vec4 clip_position = projection_matrix * view_model_matrix * vec4(v_position, 1.0);
+	clip_position.z -= offset * abs(clip_position.w);
+    gl_Position = clip_position;
 }
diff --git a/resources/shaders/gouraud.fs b/resources/shaders/gouraud.fs
index 511faf4c00..1657fc0513 100644
--- a/resources/shaders/gouraud.fs
+++ b/resources/shaders/gouraud.fs
@@ -26,8 +26,6 @@ struct SlopeDetection
 uniform vec4 uniform_color;
 uniform SlopeDetection slope;
 
-uniform bool offset_depth_buffer;
-
 #ifdef ENABLE_ENVIRONMENT_MAP
     uniform sampler2D environment_tex;
     uniform bool use_environment_tex;
@@ -78,9 +76,4 @@ void main()
     else
 #endif
         gl_FragColor = vec4(vec3(intensity.y) + color * intensity.x, alpha);
-		
-    // In the support painting gizmo and the seam painting gizmo are painted triangles rendered over the already
-    // rendered object. To resolved z-fighting between previously rendered object and painted triangles, values
-    // inside the depth buffer are offset by small epsilon for painted triangles inside those gizmos.
-    gl_FragDepth = gl_FragCoord.z - (offset_depth_buffer ? EPSILON : 0.0);
 }
diff --git a/resources/shaders/mm_contour.fs b/resources/shaders/mm_contour.fs
index 8ccf5b832c..14c18dcf16 100644
--- a/resources/shaders/mm_contour.fs
+++ b/resources/shaders/mm_contour.fs
@@ -1,11 +1,6 @@
 #version 110
 
-const float EPSILON = 0.0001;
-
 void main()
 {
     gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
-    // Values inside depth buffer for fragments of the contour of a selected area are offset
-    // by small epsilon to solve z-fighting between painted triangles and contour lines.
-    gl_FragDepth = gl_FragCoord.z - EPSILON;
 }
diff --git a/resources/shaders/mm_contour.vs b/resources/shaders/mm_contour.vs
index d0d3ee42a9..8423362e46 100644
--- a/resources/shaders/mm_contour.vs
+++ b/resources/shaders/mm_contour.vs
@@ -1,6 +1,11 @@
 #version 110
 
+uniform float offset;
+
 void main()
 {
-    gl_Position = ftransform();
+    // Add small epsilon to z to solve z-fighting between painted triangles and contour lines.
+	vec4 clip_position = gl_ModelViewProjectionMatrix * gl_Vertex;
+	clip_position.z -= offset * abs(clip_position.w);
+    gl_Position = clip_position;
 }
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index afb24185d6..2bbeb14f0d 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -5351,7 +5351,7 @@ void GLCanvas3D::_picking_pass()
 #if !ENABLE_GL_SHADERS_ATTRIBUTES
         m_camera_clipping_plane = m_gizmos.get_clipping_plane();
         if (m_camera_clipping_plane.is_active()) {
-            ::glClipPlane(GL_CLIP_PLANE0, (GLdouble*)m_camera_clipping_plane.get_data());
+            ::glClipPlane(GL_CLIP_PLANE0, (GLdouble*)m_camera_clipping_plane.get_data().data());
             ::glEnable(GL_CLIP_PLANE0);
         }
 #endif // !ENABLE_GL_SHADERS_ATTRIBUTES
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp b/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp
index c5d5405275..b6861254a9 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp
@@ -9,6 +9,7 @@
 #include "slic3r/GUI/format.hpp"
 #include "slic3r/GUI/GUI_ObjectList.hpp"
 #include "slic3r/GUI/NotificationManager.hpp"
+#include "slic3r/GUI/OpenGLManager.hpp"
 #include "libslic3r/PresetBundle.hpp"
 #include "libslic3r/Model.hpp"
 #include "slic3r/Utils/UndoRedo.hpp"
@@ -627,11 +628,8 @@ void TriangleSelectorMmGui::render(ImGuiWrapper *imgui)
 
         auto *contour_shader = wxGetApp().get_shader("mm_contour");
         contour_shader->start_using();
-
-        glsafe(::glDepthFunc(GL_LEQUAL));
+        contour_shader->set_uniform("offset", OpenGLManager::get_gl_info().is_mesa() ? 0.0005 : 0.00001);
         m_paint_contour.render();
-        glsafe(::glDepthFunc(GL_LESS));
-
         contour_shader->stop_using();
     }
 #endif // ENABLE_LEGACY_OPENGL_REMOVAL
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp b/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp
index 01dc595148..0cba59c6d8 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp
@@ -8,6 +8,7 @@
 #include "slic3r/GUI/GUI_App.hpp"
 #include "slic3r/GUI/Camera.hpp"
 #include "slic3r/GUI/Plater.hpp"
+#include "slic3r/GUI/OpenGLManager.hpp"
 #include "slic3r/Utils/UndoRedo.hpp"
 #include "libslic3r/Model.hpp"
 #include "libslic3r/PresetBundle.hpp"
@@ -284,9 +285,11 @@ void GLGizmoPainterBase::render_cursor_sphere(const Transform3d& trafo) const
 #endif // ENABLE_LEGACY_OPENGL_REMOVAL
     }
 
+#if ENABLE_LEGACY_OPENGL_REMOVAL
     GLShaderProgram* shader = wxGetApp().get_shader("flat");
     if (shader == nullptr)
         return;
+#endif // ENABLE_LEGACY_OPENGL_REMOVAL
 
     const Transform3d complete_scaling_matrix_inverse = Geometry::Transformation(trafo).get_matrix(true, true, false, true).inverse();
     const bool is_left_handed = Geometry::Transformation(trafo).is_left_handed();
@@ -918,8 +921,6 @@ void TriangleSelectorGUI::render(ImGuiWrapper* imgui)
 
     assert(shader->get_name() == "gouraud");
 
-    ScopeGuard guard([shader]() { if (shader) shader->set_uniform("offset_depth_buffer", false);});
-    shader->set_uniform("offset_depth_buffer", true);
     for (auto iva : {std::make_pair(&m_iva_enforcers, enforcers_color),
                      std::make_pair(&m_iva_blockers, blockers_color)}) {
 #if ENABLE_LEGACY_OPENGL_REMOVAL
@@ -967,11 +968,8 @@ void TriangleSelectorGUI::render(ImGuiWrapper* imgui)
 
         auto *contour_shader = wxGetApp().get_shader("mm_contour");
         contour_shader->start_using();
-
-        glsafe(::glDepthFunc(GL_LEQUAL));
+        contour_shader->set_uniform("offset", OpenGLManager::get_gl_info().is_mesa() ? 0.0005 : 0.00001);
         m_paint_contour.render();
-        glsafe(::glDepthFunc(GL_LESS));
-
         contour_shader->stop_using();
     }
 #endif // ENABLE_LEGACY_OPENGL_REMOVAL
@@ -1014,6 +1012,9 @@ void TriangleSelectorGUI::update_render_data()
         iva.release_geometry();
 #endif // ENABLE_LEGACY_OPENGL_REMOVAL
 
+    // small value used to offset triangles along their normal to avoid z-fighting
+    static const float offset = 0.001f;
+
     for (const Triangle &tr : m_triangles) {
         if (!tr.valid() || tr.is_split() || (tr.get_state() == EnforcerBlockerType::NONE && !tr.is_selected_by_seed_fill()))
             continue;
@@ -1037,15 +1038,17 @@ void TriangleSelectorGUI::update_render_data()
         //FIXME the normal may likely be pulled from m_triangle_selectors, but it may not be worth the effort
         // or the current implementation may be more cache friendly.
         const Vec3f           n   = (v1 - v0).cross(v2 - v1).normalized();
+        // small value used to offset triangles along their normal to avoid z-fighting
+        const Vec3f    offset_n   = offset * n;
 #if ENABLE_LEGACY_OPENGL_REMOVAL
-        iva.add_vertex(v0, n);
-        iva.add_vertex(v1, n);
-        iva.add_vertex(v2, n);
+        iva.add_vertex(v0 + offset_n, n);
+        iva.add_vertex(v1 + offset_n, n);
+        iva.add_vertex(v2 + offset_n, n);
         iva.add_triangle((unsigned int)cnt, (unsigned int)cnt + 1, (unsigned int)cnt + 2);
 #else
-        iva.push_geometry(v0, n);
-        iva.push_geometry(v1, n);
-        iva.push_geometry(v2, n);
+        iva.push_geometry(v0 + offset_n, n);
+        iva.push_geometry(v1 + offset_n, n);
+        iva.push_geometry(v2 + offset_n, n);
         iva.push_triangle(cnt, cnt + 1, cnt + 2);
 #endif // ENABLE_LEGACY_OPENGL_REMOVAL
         cnt += 3;
@@ -1361,16 +1364,14 @@ void TriangleSelectorGUI::render_paint_contour()
     if (contour_shader != nullptr) {
         contour_shader->start_using();
 
+        contour_shader->set_uniform("offset", OpenGLManager::get_gl_info().is_mesa() ? 0.0005 : 0.00001);
 #if ENABLE_GL_SHADERS_ATTRIBUTES
         const Camera& camera = wxGetApp().plater()->get_camera();
         contour_shader->set_uniform("view_model_matrix", camera.get_view_matrix() * matrix);
         contour_shader->set_uniform("projection_matrix", camera.get_projection_matrix());
 #endif // ENABLE_GL_SHADERS_ATTRIBUTES
 
-        glsafe(::glDepthFunc(GL_LEQUAL));
         m_paint_contour.render();
-        glsafe(::glDepthFunc(GL_LESS));
-
         contour_shader->stop_using();
     }
 
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoSimplify.cpp b/src/slic3r/GUI/Gizmos/GLGizmoSimplify.cpp
index 157a44b2ba..fcdd56c6a5 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoSimplify.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoSimplify.cpp
@@ -7,6 +7,7 @@
 #include "slic3r/GUI/NotificationManager.hpp"
 #include "slic3r/GUI/Plater.hpp"
 #include "slic3r/GUI/format.hpp"
+#include "slic3r/GUI/OpenGLManager.hpp"
 #include "libslic3r/AppConfig.hpp"
 #include "libslic3r/Model.hpp"
 #include "libslic3r/QuadricEdgeCollapse.hpp"
@@ -756,6 +757,7 @@ void GLGizmoSimplify::on_render()
         if (m_show_wireframe) {
             auto *contour_shader = wxGetApp().get_shader("mm_contour");
             contour_shader->start_using();
+            contour_shader->set_uniform("offset", OpenGLManager::get_gl_info().is_mesa() ? 0.0005 : 0.00001);
 #if ENABLE_GL_SHADERS_ATTRIBUTES
             contour_shader->set_uniform("view_model_matrix", view_model_matrix);
             contour_shader->set_uniform("projection_matrix", camera.get_projection_matrix());
diff --git a/src/slic3r/GUI/OpenGLManager.cpp b/src/slic3r/GUI/OpenGLManager.cpp
index 41a11cff6e..3bf0b1b270 100644
--- a/src/slic3r/GUI/OpenGLManager.cpp
+++ b/src/slic3r/GUI/OpenGLManager.cpp
@@ -65,6 +65,11 @@ const std::string& OpenGLManager::GLInfo::get_renderer() const
     return m_renderer;
 }
 
+bool OpenGLManager::GLInfo::is_mesa() const
+{
+    return boost::icontains(m_version, "mesa");
+}
+
 int OpenGLManager::GLInfo::get_max_tex_size() const
 {
     if (!m_detected)
diff --git a/src/slic3r/GUI/OpenGLManager.hpp b/src/slic3r/GUI/OpenGLManager.hpp
index 72a4e6bc07..0b505c6455 100644
--- a/src/slic3r/GUI/OpenGLManager.hpp
+++ b/src/slic3r/GUI/OpenGLManager.hpp
@@ -40,6 +40,8 @@ public:
         const std::string& get_vendor() const;
         const std::string& get_renderer() const;
 
+        bool is_mesa() const;
+
         int get_max_tex_size() const;
         float get_max_anisotropy() const;