From 58defb3c05ce9e98ff1ebc81d7a34b6b68f35b43 Mon Sep 17 00:00:00 2001
From: Steven Brown <steven.brown@xero.com>
Date: Fri, 13 Oct 2017 11:23:06 +1300
Subject: [PATCH] fixed scrolling

---
 display_centre.py | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/display_centre.py b/display_centre.py
index 351485b..d819808 100644
--- a/display_centre.py
+++ b/display_centre.py
@@ -139,8 +139,9 @@ def move_browser_selection_up():
     global browser_index
     global browser_start_index
     if browser_index == 0:
-        browser_start_index = browser_start_index - 1
-        refresh_display()
+        if(browser_start_index > 0):
+            browser_start_index = browser_start_index - 1
+            refresh_display()
         return
     display.tag_remove("SELECT", ROW_OFFSET + browser_index,
                        ROW_OFFSET + SELECTOR_WIDTH + browser_index)
@@ -157,8 +158,9 @@ def move_browser_selection_down():
     last_index = len(data_object.get_browser_data_for_display()) - 1
     if browser_index >= last_index:
         return
-    
-    if browser_index >= MAX_LINES -1:
+    if browser_index + browser_start_index >= last_index:
+        return
+    if browser_index >= MAX_LINES - 1:
         browser_start_index = browser_start_index + 1
         refresh_display()
         return