[meld] Minor fix for editable state handling in linkmap

[Kai Willadsen <kaiw src gnome org>]

commit 70a9426918f7a74de46da8df053e529c9c3618be
Author: Piotr Piastucki <the_leech users berlios de>
Date:   Tue Apr 5 21:50:59 2011 +0200

    Minor fix for editable state handling in linkmap

 meld/linkmap.py |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/meld/linkmap.py b/meld/linkmap.py
index d0f5c78..5b20bfd 100644
--- a/meld/linkmap.py
+++ b/meld/linkmap.py
@@ -121,11 +121,13 @@ class LinkMap(gtk.DrawingArea):
         left_act, right_act = None, None
         if change_type == "delete":
             left_act = MODE_REPLACE
-            if self.mode == MODE_DELETE and left_editable:
+            if (self.mode == MODE_DELETE or not right_editable) and \
+               left_editable:
                 left_act = MODE_DELETE
         elif change_type == "insert":
             right_act = MODE_REPLACE
-            if self.mode == MODE_DELETE and right_editable:
+            if (self.mode == MODE_DELETE or not left_editable) and \
+               right_editable:
                 right_act = MODE_DELETE
         elif change_type == "replace":
             if not left_editable: