diff --git a/FL/Fl_Input.H b/FL/Fl_Input.H
index f165ddc6e..0967d332f 100644
--- a/FL/Fl_Input.H
+++ b/FL/Fl_Input.H
@@ -1,7 +1,7 @@
 //
 // Input header file for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2010 by Bill Spitzak and others.
+// Copyright 1998-2021 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -34,7 +34,7 @@
   Character composition is done using dead keys and/or a compose
   key as defined by the operating system.
   <P>
- <!-- DON'T use the class name in the caption, or doxygen 1.8.x will fail. -->
+  <!-- DON'T use the class name in the caption, or doxygen 1.8.x will fail. -->
   <TABLE WIDTH="90%" BORDER="1" SUMMARY="Fl_Input keyboard and mouse bindings.">
     <CAPTION ALIGN="TOP">Keyboard and mouse bindings.</CAPTION>
     <TR><TD NOWRAP="NOWRAP" WIDTH="1%">
@@ -220,7 +220,6 @@
 class FL_EXPORT Fl_Input : public Fl_Input_ {
   friend class Fl_Screen_Driver;
   friend class Fl_Cocoa_Screen_Driver; // Not ideal, but probably no other platform will use it
-  int handle_key();
   int shift_position(int p);
   int shift_up_down_position(int p);
   void handle_mouse(int keepmark=0);
@@ -257,6 +256,8 @@ class FL_EXPORT Fl_Input : public Fl_Input_ {
 
 protected:
   void draw();
+  int handle_key();
+
 public:
   int handle(int);
   Fl_Input(int,int,int,int,const char * = 0);
diff --git a/src/Fl_Input.cxx b/src/Fl_Input.cxx
index 9a3342eb2..5fa16bfb0 100644
--- a/src/Fl_Input.cxx
+++ b/src/Fl_Input.cxx
@@ -1,7 +1,7 @@
 //
 // Input widget for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2020 by Bill Spitzak and others.
+// Copyright 1998-2021 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -300,9 +300,17 @@ int Fl_Input::kf_copy_cut() {
   return cut();
 }
 
-// Handle a keystroke.
-//     Returns 1 if handled by us, 0 if not.
-//
+/** Handles a keystroke.
+
+  This \p protected method handles a keystroke in an Fl_Input or derived
+  class. It handles compose key sequences and can also be used e.g. in
+  Fl_Multiline_Input, Fl_Float_Input and several more derived classes.
+
+  The details are way too complicated to be documented here and can be
+  changed as required. If in doubt, please consult the source code.
+
+  \returns  1 if the keystroke is handled by us, 0 if not.
+*/
 int Fl_Input::handle_key() {
 
   char ascii = Fl::event_text()[0];