athen---introduction-to-the-texteditor.md

@@ -168,3 +168,13 @@ If one inspects the code of ```initEventHandler()``` one can directly see the ha
 		}
 
 ```
+The first part adds a listener to the vertical bar, **IF** it is available. Once we receive an event by the scrollbar we need to do two things:
+
+1. save the position of the bar (the value is in lines of the editor) (this enables us to start drawing the line which is below the top visible offset)
+2. and update the widget so that the correct text is displayed
+
+Analogous we can inspect the listener to the horizontal scrollbar, we also notice two operations:
+1. save the position of the scrollbar and store it in the variable ```leftMostPosition``` the value is this time given in pixel
+2. update the widget so that the correct text is displayed
+
+both bars are set invisible initially