diff --git a/CHANGES b/CHANGES
index 813260a4b..c5f3e9895 100644
--- a/CHANGES
+++ b/CHANGES
@@ -9,6 +9,8 @@ CHANGES IN FLTK 1.1.10
 	  function (STR #1945)
 	- Fl_Group and Fl_Scroll now resize themselves before
 	  resizing their children (STR #2032)
+	- Fixed adding an idle handler during
+	  a draw() call (STR #1950)
 
 CHANGES IN FLTK 1.1.9
 
diff --git a/src/Fl.cxx b/src/Fl.cxx
index dde61972d..4e25c7b61 100644
--- a/src/Fl.cxx
+++ b/src/Fl.cxx
@@ -323,6 +323,8 @@ double Fl::wait(double time_to_wait) {
     if (idle) time_to_wait = 0.0;
   }
   flush();
+  if (idle && !in_idle) // 'idle' may have been set within flush()
+    time_to_wait = 0.0;
   return fl_wait(time_to_wait);
 
 #else
@@ -369,6 +371,8 @@ double Fl::wait(double time_to_wait) {
   } else {
     // do flush first so that user sees the display:
     flush();
+    if (idle && !in_idle) // 'idle' may have been set within flush()
+      time_to_wait = 0.0;
     return fl_wait(time_to_wait);
   }
 #endif
diff --git a/test/mandelbrot.cxx b/test/mandelbrot.cxx
index 43ef78092..1c89aef94 100644
--- a/test/mandelbrot.cxx
+++ b/test/mandelbrot.cxx
@@ -33,12 +33,12 @@
 Drawing_Window mbrot;
 Drawing_Window jbrot;
 
-void idle() {
-  if (!mbrot.d->idle() && !(jbrot.d && jbrot.d->idle())) Fl::set_idle(0);
+void idle(void*) {
+  if (!mbrot.d->idle() && !(jbrot.d && jbrot.d->idle())) Fl::remove_idle(idle);
 }
 
 void set_idle() {
-  Fl::set_idle(idle);
+  Fl::add_idle(idle);
 }
 
 static void window_callback(Fl_Widget*, void*) {exit(0);}