patch.diff

diff --git a/lib/outputrenderers.php b/lib/outputrenderers.php
index 7b705a91be..00bfdc2810 100644
--- a/lib/outputrenderers.php
+++ b/lib/outputrenderers.php
@@ -1833,6 +1833,13 @@ class core_renderer extends renderer_base {
             if (empty($zones)) {
                 // There are no zones, probably because there are no blocks.
                 $regions = $this->page->theme->get_all_block_regions();
+                // Append the eventually injected custom regions.
+                foreach ($this->page->blocks->get_regions() as $regioninternalname) {
+                    if (!isset($regions[$regioninternalname])) {
+                        $regions[$regioninternalname] = $regioninternalname;
+                    }
+                }
+
                 $position = get_string('moveblockinregion', 'block', $regions[$region]);
             } else {
                 $position = get_string('moveblockbefore', 'block', $zones[0]);