diff --git a/lib/Slic3r/GUI/3DScene.pm b/lib/Slic3r/GUI/3DScene.pm
index e5990fe8d5..13460cfed2 100644
--- a/lib/Slic3r/GUI/3DScene.pm
+++ b/lib/Slic3r/GUI/3DScene.pm
@@ -1527,10 +1527,13 @@ sub draw_active_object_annotations {
     my ($reset_left, $reset_bottom, $reset_right, $reset_top) = $self->_variable_layer_thickness_reset_rect_viewport;
     my $z_cursor_relative = $self->_variable_layer_thickness_bar_mouse_cursor_z_relative;
 
+    my $print_object = $self->{print}->get_object($object_idx);
+    my $z_max = $print_object->model_object->bounding_box->z_max;
+    
     $self->{layer_height_edit_shader}->enable;
     $self->{layer_height_edit_shader}->set_uniform('z_to_texture_row',            $volume->layer_height_texture_z_to_row_id);
     $self->{layer_height_edit_shader}->set_uniform('z_texture_row_to_normalized', 1. / $volume->layer_height_texture_height);
-    $self->{layer_height_edit_shader}->set_uniform('z_cursor',                    $volume->bounding_box->z_max * $z_cursor_relative);
+    $self->{layer_height_edit_shader}->set_uniform('z_cursor',                    $z_max * $z_cursor_relative);
     $self->{layer_height_edit_shader}->set_uniform('z_cursor_band_width',         $self->{layer_height_edit_band_width});
     glBindTexture(GL_TEXTURE_2D, $self->{layer_preview_z_texture_id});
     glTexImage2D_c(GL_TEXTURE_2D, 0, GL_RGBA8, $volume->layer_height_texture_width, $volume->layer_height_texture_height, 
@@ -1552,8 +1555,8 @@ sub draw_active_object_annotations {
     glBegin(GL_QUADS);
     glVertex3f($bar_left,  $bar_bottom, 0);
     glVertex3f($bar_right, $bar_bottom, 0);
-    glVertex3f($bar_right, $bar_top, $volume->bounding_box->z_max);
-    glVertex3f($bar_left,  $bar_top, $volume->bounding_box->z_max);
+    glVertex3f($bar_right, $bar_top, $z_max);
+    glVertex3f($bar_left,  $bar_top, $z_max);
     glEnd();
     glBindTexture(GL_TEXTURE_2D, 0);
     $self->{layer_height_edit_shader}->disable;
@@ -1572,7 +1575,6 @@ sub draw_active_object_annotations {
 
     # Paint the graph.
     #FIXME show some kind of legend.
-    my $print_object = $self->{print}->get_object($object_idx);
     my $max_z = unscale($print_object->size->z);
     my $profile = $print_object->model_object->layer_height_profile;
     my $layer_height = $print_object->config->get('layer_height');
@@ -1934,8 +1936,6 @@ const vec3 LIGHT_FRONT_DIR = vec3(0.6985074, 0.1397015, 0.6985074);
 
 #define INTENSITY_AMBIENT    0.3
 
-uniform float z_to_texture_row;
-
 // x = tainted, y = specular;
 varying vec2 intensity;
 
diff --git a/xs/src/slic3r/GUI/3DScene.cpp b/xs/src/slic3r/GUI/3DScene.cpp
index 1ce3d76bfd..a33ef4d1c6 100644
--- a/xs/src/slic3r/GUI/3DScene.cpp
+++ b/xs/src/slic3r/GUI/3DScene.cpp
@@ -305,7 +305,7 @@ void GLVolume::render_using_layer_height() const
         glUniform1f(z_texture_row_to_normalized_id, (GLfloat)(1.0f / layer_height_texture_height()));
 
     if (z_cursor_id >= 0)
-        glUniform1f(z_cursor_id, (GLfloat)(bounding_box.max.z * layer_height_texture_data.z_cursor_relative));
+        glUniform1f(z_cursor_id, (GLfloat)(layer_height_texture_data.print_object->model_object()->bounding_box().max.z * layer_height_texture_data.z_cursor_relative));
 
     if (z_cursor_band_width_id >= 0)
         glUniform1f(z_cursor_band_width_id, (GLfloat)layer_height_texture_data.edit_band_width);
@@ -327,6 +327,11 @@ void GLVolume::render_using_layer_height() const
         glUseProgram(current_program_id);
 }
 
+double GLVolume::layer_height_texture_z_to_row_id() const
+{
+    return (this->layer_height_texture.get() == nullptr) ? 0.0 : double(this->layer_height_texture->cells - 1) / (double(this->layer_height_texture->width) * this->layer_height_texture_data.print_object->model_object()->bounding_box().max.z);
+}
+
 void GLVolume::generate_layer_height_texture(PrintObject *print_object, bool force)
 {
     GLTexture *tex = this->layer_height_texture.get();
diff --git a/xs/src/slic3r/GUI/3DScene.hpp b/xs/src/slic3r/GUI/3DScene.hpp
index 6486a7f0e7..380206dd97 100644
--- a/xs/src/slic3r/GUI/3DScene.hpp
+++ b/xs/src/slic3r/GUI/3DScene.hpp
@@ -361,10 +361,7 @@ public:
         return (layer_height_texture.get() == nullptr) ? 0 :
             (void*)(layer_height_texture->data.data() + layer_height_texture->width * layer_height_texture->height * 4);
     }
-    double              layer_height_texture_z_to_row_id() const { 
-        return (this->layer_height_texture.get() == nullptr) ? 0. : 
-            double(this->layer_height_texture->cells - 1) / (double(this->layer_height_texture->width) * bounding_box.max.z);
-    }
+    double              layer_height_texture_z_to_row_id() const;
     void                generate_layer_height_texture(PrintObject *print_object, bool force);
 
     void set_layer_height_texture_data(unsigned int texture_id, unsigned int shader_id, PrintObject* print_object, float z_cursor_relative, float edit_band_width)