commit a8ca8ec1eecea792e50ae55b90b8129ab4f6ffc0
Author: Joel Pittet <joel@pittet.ca>
Date:   Mon Aug 17 09:42:00 2015 -0700

    added doc

diff --git a/core/modules/block/js/block.js b/core/modules/block/js/block.js
index c3b9d6d..edc953b 100644
--- a/core/modules/block/js/block.js
+++ b/core/modules/block/js/block.js
@@ -132,6 +132,10 @@
         // Update the block weights.
         $table.find('.region-' + region + '-message').nextUntil('.region-title')
           .find('select.block-weight').val(function () {
+            // Increment the weight before assigning it to prevent using the
+            // absolute minimum available weight. This way we always have an
+            // unused upper and lower bound, which makes manually setting the
+            // weights easier for users who prefer to do it that way.
             return ++weight;
           });
       };