diff --git a/layergen.py b/layergen.py
index f9fc702..6e14cba 100644
--- a/layergen.py
+++ b/layergen.py
@@ -292,7 +292,7 @@ class mstr_layergen:
             for s in range(len(src)):
                 srcstr = srcstr + str(src[s])
                 if s < len(src)-1:
-                    srcstr = strsrc + ","
+                    srcstr = srcstr + ","
 
             # Patch and border sources. There can only be one for each.
             brd_src = None