Improve prioritization of event handlers added at open display time

1 files changed, 9 insertions, 7 deletions

diff --git a/src/Fl_Screen_Driver.cxx b/src/Fl_Screen_Driver.cxx
index d127b6b1e..112f376d3 100644
--- a/src/Fl_Screen_Driver.cxx
+++ b/src/Fl_Screen_Driver.cxx
@@ -571,21 +571,23 @@ void Fl_Screen_Driver::use_startup_scale_factor()
 void Fl_Screen_Driver::open_display()
 {
   static bool been_here = false;
-  // Add scale_handler first so it has least priority of all handlers
-  if (!been_here) Fl::add_handler(Fl_Screen_Driver::scale_handler);
-  open_display_platform();
   if (!been_here) {
     been_here = true;
-    bool keep_scale_handler = false;
+    open_display_platform();
+    // Memorize the most recently added handler. It may have been
+    // added by open_display_platform()
+    Fl_Event_Handler last_added = Fl::last_handler();
     if (rescalable()) {
       use_startup_scale_factor();
-      if (keyboard_screen_scaling && rescalable())
-        keep_scale_handler = true;
+      if (keyboard_screen_scaling && rescalable()) {
+        // Add scale_handler after memorized one in linked list
+        // so it has less priority
+        Fl::add_handler(Fl_Screen_Driver::scale_handler, last_added);
+      }
       int mx, my;
       int ns = Fl::screen_driver()->get_mouse(mx, my);
       Fl_Graphics_Driver::default_driver().scale(scale(ns));
     }
-    if (!keep_scale_handler) Fl::remove_handler(Fl_Screen_Driver::scale_handler);
   }
 }