diff --git a/fcore/app-update.sml b/fcore/app-update.sml
index da5f781..e76cbcb 100644
--- a/fcore/app-update.sml
+++ b/fcore/app-update.sml
@@ -24,13 +24,16 @@ struct
       let
         val {windowWidth, windowHeight, startLine, ...} = app
 
-        (* move LineGap to first line displayed on screen, and build new text *)
-        val buffer = 
-          LineGap.goToLine (startLine, buffer)
+        (* move LineGap to first line displayed on screen *)
+        val buffer = LineGap.goToLine (startLine, buffer)
 
+        (* get new startLine which may move screen depending on cursor movements *)
         val startLine = TextWindow.getStartLine
           (buffer, startLine, cursorIdx, windowWidth, windowHeight)
 
+        (* move buffer to new startLine as required by TextBuilder.build *)
+        val buffer = LineGap.goToLine (startLine, buffer)
+
         val drawMsg = 
           TextBuilder.build
             (startLine, cursorIdx, buffer, windowWidth, windowHeight)
@@ -59,14 +62,17 @@ struct
     if count = 0 then
       let
         val {windowWidth, windowHeight, startLine, ...} = app
-        (* todo: get new startLine if cursor has moved out of screen *)
 
-        (* move LineGap to first line displayed on screen, and build new text *)
+        (* move LineGap to first line displayed on screen *)
         val buffer = LineGap.goToLine (startLine, buffer)
 
+        (* get new startLine which may move screen depending on cursor movements *)
         val startLine = TextWindow.getStartLine
           (buffer, startLine, cursorIdx, windowWidth, windowHeight)
 
+        (* move buffer to new startLine as required by TextBuilder.build *)
+        val buffer = LineGap.goToLine (startLine, buffer)
+
         val drawMsg = TextBuilder.build
           (startLine, cursorIdx, buffer, windowWidth, windowHeight)
 
diff --git a/fcore/text-window.sml b/fcore/text-window.sml
index 971c2bb..97c30ba 100644
--- a/fcore/text-window.sml
+++ b/fcore/text-window.sml
@@ -65,7 +65,7 @@ struct
               if curHeight + (ySpace * 3) >= maxHeight then
                 getStartLineAfter 
                   ( sIdx + 1, shd, lineNum + 1, absIdx + 1, cursorIdx, stl
-                  , maxWidth, maxHeight, 0, 0
+                  , maxWidth, maxHeight, 0, curHeight + ySpace
                   , origLine + 1
                   )
               else
@@ -90,13 +90,13 @@ struct
                 if curHeight + (ySpace * 3) >= maxHeight then
                   getStartLineAfter
                     ( sIdx + 1, shd, lineNum + 1, absIdx + 1, cursorIdx, stl
-                    , maxWidth, maxHeight, 0, 0
+                    , maxWidth, maxHeight, 0, curHeight + ySpace
                     , origLine + 1
                     )
                 else
                   getStartLineAfter
                     ( sIdx + 1, shd, lineNum + 1, absIdx + 1, cursorIdx, stl
-                    , maxWidth, maxHeight, 0, 0
+                    , maxWidth, maxHeight, 0, curHeight + ySpace
                     , origLine
                     )
           end
@@ -132,12 +132,11 @@ struct
                 (startIdx + 1, rStrHd, oldLine, absIdx + 1, cursorIdx, leftStrings)
             else if cursorIdx > absIdx then
               (* possibly move downwards *)
-              let val _ = print "start 133\n" in
               getStartLineAfter 
                  ( startIdx, rStrHd, oldLine, absIdx, cursorIdx, rStrTl
                  , maxWidth, maxHeight, 0, 0
                  , oldLine
-                 ) end
+                 )
             else
               (* keep current line *)
               Int.max (oldLine - 1, 0)
diff --git a/shf b/shf
index cd46eb6..492b64c 100755
Binary files a/shf and b/shf differ