gistfile1.txt

diff --git a/src/main/java/edu/mit/blocks/renderable/BlockLabel.java b/src/main/java/edu/mit/blocks/renderable/BlockLabel.java
index 2a79974..23a7728 100644
--- a/src/main/java/edu/mit/blocks/renderable/BlockLabel.java
+++ b/src/main/java/edu/mit/blocks/renderable/BlockLabel.java
@@ -268,6 +268,7 @@
             Block oldBlock = workspace.getEnv().getBlock(blockID);
             oldBlock.changeGenusTo(genus);
             RenderableBlock rb = workspace.getEnv().getRenderableBlock(blockID);
+            rb.setBlockToolTip(oldBlock.getBlockDescription());
             rb.repaintBlock();
             workspace.notifyListeners(new WorkspaceEvent(workspace, rb.getParentWidget(), blockID, WorkspaceEvent.BLOCK_GENUS_CHANGED));
         }