--- a/FlyByHelp.st	Fri Jan 19 10:43:10 2018 +0100
+++ b/FlyByHelp.st	Fri Jan 19 10:43:24 2018 +0100
@@ -36,6 +36,27 @@
 "
 !
 
+documentation
+"
+    an instance of me is used to provide tooltips 
+    (sigh: smalltalk was ahead of its time in the early 90's:
+     initially called 'activeHelp', then renamed to 'flyByHelp' 
+     and now commonly known as tooltip).
+
+    I will watch the mouse movements via an event hook, and determine
+    where the mouse pointer is. Then ask the underlying view about its
+    helpText and display it in a little floating popup view.
+
+    The hool is installed via:
+     FlyByHelp start
+    and possibly deactivated/uninstalled via:
+     FlyByHelp stop
+
+    There can be only one FlyByHelp at any time - the start/stop methods
+    assure that.
+"
+!
+
 examples
 "
     UserPreferences current toolTipShapeStyle:nil
@@ -85,8 +106,8 @@
         ^ false
     ].
 
-    "/ don't start tooltip, if this view is not active
-    "/ does not work, because motion events are reported for the current focus-view,
+    "/ don't start tooltip, if this view is not active.
+    "/ The following line does not work, because motion events are reported for the current focus-view,
     "/ which is always active. Must check after we have determined the view under the pointer
     "/      aView topView isActive ifFalse:[^ false].