diff --git a/application.py b/application.py
index bd41ed4..c84ff7e 100755
--- a/application.py
+++ b/application.py
@@ -562,7 +562,8 @@ class Application(object):
                 if p.y == y and p.x >= x and p.x < x + swidth:
                     (vy, vx) = (slot.y_offset + count, p.x - x + w.mode.lmargin)
                     break
-                if x + swidth >= len(w.buffer.lines[y]):
+
+                if y >= len(w.buffer.lines) or x + swidth >= len(w.buffer.lines[y]):
                     x = 0
                     y += 1
                 else: