Index: app/paint-funcs/paint-funcs.c
===================================================================
--- app/paint-funcs/paint-funcs.c	(revision 26527)
+++ app/paint-funcs/paint-funcs.c	(working copy)
@@ -1422,6 +1422,7 @@
       if (new_alpha)
         {
           guint ratio = *m * opacity;
+          ratio = ratio / 255 * src2_alpha;
 
           ratio = INT_DIV (ratio, new_alpha);
 
