STR#2052 fixed. Also added documentation to FL_File_Input explaining …

…what events the user can handle and also an application note explaining how to avoid potential callback reentrant calls.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@6386 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

FL/Fl_File_Input.H

@@ -40,8 +40,15 @@
 
   A navigation bar located above the input field allows the user to
   navigate upward in the directory tree.
-
-  \image html Fl_File_Input.gif
+  You may want to handle FL_WHEN_CHANGED events for tracking text changes
+  and also FL_WHEN_RELEASE for button release when changing to parent dir.
+  FL_WHEN_RELEASE callback won't be called if the directory clicked 
+  is the same that the current one.
+  <P align=CENTER> \image html Fl_File_Input.gif </P>
+  \note As all Fl_Input derived objects, Fl_File_Input may call its callback
+  when loosing focus (see FL_UNFOCUS) to update its state like its cursor shape.
+  One resulting side effect is that you should call clear_changed() early in your callback
+  to avoid reentrant calls if you plan to show another window or dialog box in the callback.
 */
 class FL_EXPORT Fl_File_Input : public Fl_Input
 {

src/Fl_File_Input.cxx

@@ -278,7 +278,7 @@ Fl_File_Input::handle_button(int event)		// I - Event
 
     // Then do the callbacks, if necessary...
     set_changed();
-    if (when() & FL_WHEN_CHANGED) do_callback();
+    if (when() & (FL_WHEN_CHANGED|FL_WHEN_RELEASE) ) do_callback();
   }
 
   return 1;