diff --git a/documentation/src/opengl.dox b/documentation/src/opengl.dox
index c1ce8a9fd..0e538a13a 100644
--- a/documentation/src/opengl.dox
+++ b/documentation/src/opengl.dox
@@ -155,7 +155,7 @@ OpenGL window.
 HighDPI displays (including the so-called 'retina' displays of Apple
 hardware) are supported by FLTK in such a way that 1 unit of an FLTK
 quantity (say, the value given by Fl_Gl_Window::w()) corresponds to more
-than 1 pixel on the display. Conversely, when a program specifies the width and height of the
+than 1 pixel on the display. Consequently, when a program specifies the width and height of the
 OpenGL viewport, it is necessary to use an API that returns quantities expressed in pixels.
 That can be done as follows:
 \code
@@ -164,9 +164,13 @@ That can be done as follows:
 \endcode
 which makes use of the Fl_Gl_Window::pixel_w() and Fl_Gl_Window::pixel_h() methods giving
 the size in pixels of an Fl_Gl_Window that is potentially mapped to a HighDPI display.
-Method Fl_Gl_Window::pixels_per_unit() can also be useful in this context.
-\note A further coding rule is necessary to properly support retina displays
-and OpenGL under macOS (see \ref osissues_retina)
+
+Method Fl_Gl_Window::pixels_per_unit() can be useful when the OpenGL code depends on
+the pixel dimension of the GL scene. This occurs, e.g., if a window's handle() method
+uses Fl::event_x() and Fl::event_y() whose returned values should be multiplied by
+Fl_Gl_Window::pixels_per_unit() to obtain the adequate pixel units.
+This method may also be useful, for example, to adjust the width of a line in a
+high resolution GL scene.
 
 \section opengl_normal Using OpenGL in Normal FLTK Windows
 
diff --git a/documentation/src/osissues.dox b/documentation/src/osissues.dox
index ce8a7fa74..d7d8fc030 100644
--- a/documentation/src/osissues.dox
+++ b/documentation/src/osissues.dox
@@ -931,34 +931,6 @@ Set <tt>"Print Front Window" = "";</tt> therein so the application menu doesn't
 To localize the application name itself, create a file <tt>InfoPlist.strings</tt> in each .lproj directory
 and put <tt>CFBundleName = "localized name";</tt> in each such file.
 
-\subsection osissues_retina OpenGL and 'retina' displays
-It is possible to have OpenGL produce graphics at the high pixel resolution allowed by the so-called 'retina' displays
-present on recent Apple hardware.
-For this, call
-\verbatim
-Fl::use_high_res_GL(1);
-\endverbatim
-before any Fl_Gl_Window is shown. Also, adapt your Fl_Gl_Window::draw() and Fl_Gl_Window::draw_overlay() methods replacing
-\verbatim
-glViewport(0, 0, w(), h());
-\endverbatim
-by
-\verbatim
-glViewport(0, 0, pixel_w(), pixel_h());
-\endverbatim
-making use of the Fl_Gl_Window::pixel_w() and Fl_Gl_Window::pixel_h() methods that return the width and height of
-the GL scene in pixels: if the Fl_Gl_Window is mapped on a retina display, these methods return twice as much as
-reported by Fl_Widget::w() and Fl_Widget::h(); if it's mapped on a regular display, they return the same values
-as w() and h(). These methods dynamically change their values if the window is moved into/out from a retina
-display. If Fl::use_high_res_GL(1) is not called, all Fl_Gl_Window 's are drawn at low resolution.
-These methods are useful on all platforms because Fl_Gl_Window::w() and Fl_Gl_Window::h() don't return,
-on HighDPI displays, the quantitites in pixels necessary to OpenGL functions .
-
-The Fl_Gl_Window::pixels_per_unit() method is useful when the OpenGL code depends on the pixel dimension
-of the GL scene. This occurs, e.g., if a window's handle() method uses Fl::event_x() and Fl::event_y()
-whose returned values should be multiplied by Fl_Gl_Window::pixels_per_unit() to obtain the adequate pixel units.
-This method may also be useful, for example, to adjust the width of a line in a high resolution GL scene.
-
 \subsection double_window Fl_Double_Window
 
 OS X double-buffers all windows automatically. On OS X, Fl_Window and Fl_Double_Window are handled
diff --git a/examples/OpenGL3-glut-test.cxx b/examples/OpenGL3-glut-test.cxx
index 8693b3861..1c3371999 100644
--- a/examples/OpenGL3-glut-test.cxx
+++ b/examples/OpenGL3-glut-test.cxx
@@ -192,7 +192,6 @@ int fullscreen = 0;
 
 int main (int argc, char* argv[])
 {
-  Fl::use_high_res_GL(true);
   glutInit(&argc, argv);
   glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | FL_OPENGL3);
   glutInitWindowSize(400, 400);
diff --git a/examples/OpenGL3test.cxx b/examples/OpenGL3test.cxx
index c9f0d59e5..c65e9eb8b 100644
--- a/examples/OpenGL3test.cxx
+++ b/examples/OpenGL3test.cxx
@@ -250,7 +250,6 @@ void add_widgets(Fl_Gl_Window *g) {
 
 int main(int argc, char **argv)
 {
-  Fl::use_high_res_GL(1);
   Fl_Window *topwin = new Fl_Window(800, 300);
   SimpleGL3Window *win = new SimpleGL3Window(0, 0, 300, 300);
   win->end();
diff --git a/src/Fl.cxx b/src/Fl.cxx
index 894897419..2cf5a41b0 100644
--- a/src/Fl.cxx
+++ b/src/Fl.cxx
@@ -2258,20 +2258,22 @@ Fl_Widget_Tracker::~Fl_Widget_Tracker()
   Fl::release_widget_pointer(wp_); // remove pointer from watch list
 }
 
-int Fl::Private::use_high_res_GL_ = 0;
+int Fl::Private::use_high_res_GL_ = 1; // default value changed beginning FLTK 1.5
 
-/**  sets whether GL windows should be drawn at high resolution on Apple
-  computers with retina displays
-  \version 1.3.4
+/**  Sets whether GL windows should be drawn at high resolution on Apple
+  computers with retina displays.
+ Because the default value is \c 1, this function is useful only in the very unlikely situation where a macOS app
+ would choose to draw low resolution GL graphics when mapped on a retina display.
+ This function has effect only under macOS.
+ \version 1.3.4 (default value changed in 1.5)
  */
 void Fl::use_high_res_GL(int val) {
   Private::use_high_res_GL_ = val;
 }
 
-/**  returns whether GL windows should be drawn at high resolution on Apple
+/**  Returns whether GL windows should be drawn at high resolution on Apple
   computers with retina displays.
-  Default is no.
-  \version 1.3.4
+  \version Default value set to 1 starting with FLTK 1.5
  */
 int Fl::use_high_res_GL() {
   return Private::use_high_res_GL_;
diff --git a/test/CubeView.cxx b/test/CubeView.cxx
index f2890d569..e2dc3f2a4 100644
--- a/test/CubeView.cxx
+++ b/test/CubeView.cxx
@@ -31,7 +31,6 @@ CubeView::CubeView(int x, int y, int w, int h, const char *l)
   : Fl_Box(x, y, w, h, l)
 #endif /* HAVE_GL */
 {
-  Fl::use_high_res_GL(1);
   vAng = 0.0;
   hAng = 0.0;
   size = 10.0;
diff --git a/test/cube.cxx b/test/cube.cxx
index 609922762..69fb3ed88 100644
--- a/test/cube.cxx
+++ b/test/cube.cxx
@@ -388,7 +388,6 @@ void makeform(const char *name) {
 }
 
 int main(int argc, char **argv) {
-  Fl::use_high_res_GL(1);
   Fl::set_color(FL_FREE_COLOR, 255, 255, 0, 75);
   makeform(argv[0]);
 
diff --git a/test/fractals.cxx b/test/fractals.cxx
index 5e3839d03..af7aab9e9 100644
--- a/test/fractals.cxx
+++ b/test/fractals.cxx
@@ -767,7 +767,6 @@ void handlemenu(Fl_Widget*, void *value) {handlemenu(fl_int(value));}
 
 int main(int argc, char** argv)
 {
-  Fl::use_high_res_GL(1);
 //  glutInit(&argc, argv); // this line removed for FLTK
 
   // create FLTK window:
diff --git a/test/fullscreen.cxx b/test/fullscreen.cxx
index 56432859e..ea1fcd28c 100644
--- a/test/fullscreen.cxx
+++ b/test/fullscreen.cxx
@@ -281,7 +281,6 @@ int arg(int, char **argv, int &i) {
 
 int main(int argc, char **argv) {
 
-  Fl::use_high_res_GL(1);
   int i=0;
   if (Fl::args(argc,argv,i,arg) < argc)
     Fl::fatal("Options are:\n -2 = 2 windows\n -f = startup fullscreen\n%s",Fl::help);
diff --git a/test/gl_image.cxx b/test/gl_image.cxx
index 3f64846e1..d877a6641 100644
--- a/test/gl_image.cxx
+++ b/test/gl_image.cxx
@@ -105,7 +105,6 @@ void chooser_cb(Fl_Widget *, Gl_Image_Window *mainwin) {
 
 
 int main(int argc, char **argv) {
-  Fl::use_high_res_GL(1);
   fl_register_images();
   Gl_Image_Window mainwin(600, 600, "GL Image Viewer");
   mainwin.show(argc, argv);
diff --git a/test/gl_overlay.cxx b/test/gl_overlay.cxx
index 3d46377bc..958aa3fe3 100644
--- a/test/gl_overlay.cxx
+++ b/test/gl_overlay.cxx
@@ -106,7 +106,6 @@ void overlay_sides_cb(Fl_Widget *o, void *p) {
 #include <stdio.h>
 int main(int argc, char **argv) {
 
-  Fl::use_high_res_GL(1);
   Fl_Window window(300, 370);
 
   shape_window sw(10, 75, window.w()-20, window.h()-90);
diff --git a/test/glpuzzle.cxx b/test/glpuzzle.cxx
index a05c26535..9489253be 100644
--- a/test/glpuzzle.cxx
+++ b/test/glpuzzle.cxx
@@ -1449,7 +1449,6 @@ main(int argc, char **argv)
 {
   long i;
 
-  Fl::use_high_res_GL(1);
   glutInit(&argc, argv);
   for (i = 1; i < argc; i++) {
     if (argv[i][0] == '-') {
diff --git a/test/shape.cxx b/test/shape.cxx
index 962e66473..8d58e1f45 100644
--- a/test/shape.cxx
+++ b/test/shape.cxx
@@ -79,7 +79,6 @@ void sides_cb(Fl_Widget *o, void *p) {
 
 int main(int argc, char **argv) {
 
-  Fl::use_high_res_GL(1);
   Fl_Window window(300, 330);
 
 // the shape window could be it's own window, but here we make it
diff --git a/test/unittests.cxx b/test/unittests.cxx
index 7d537cc75..ceb3ba18e 100644
--- a/test/unittests.cxx
+++ b/test/unittests.cxx
@@ -450,7 +450,6 @@ int main(int argc, char** argv) {
   Fl::get_system_colors();
   Fl::scheme(Fl::scheme()); // init scheme before instantiating tests
   Fl::visual(FL_RGB);
-  Fl::use_high_res_GL(1);
   mainwin = new Ut_Main_Window(UT_MAINWIN_W, UT_MAINWIN_H, "FLTK Unit Tests");
   mainwin->size_range(UT_MAINWIN_W, UT_MAINWIN_H);
   browser = new Fl_Hold_Browser(UT_BROWSER_X, UT_BROWSER_Y, UT_BROWSER_W, UT_BROWSER_H, "Unit Tests");