Added a workaround for onBlockDestroy providing (0, 0, 0). Setting air no longer sets the data.

src/EditSession.java

@@ -113,9 +113,10 @@ public class EditSession {
      */
     private boolean rawSetBlock(Vector pt, BaseBlock block) {
         boolean result = server.setBlockType(pt, block.getID());
+        if (block.getID() != 0) {
             // Changes in block data don't take effect if the block type doesn't
             // change, so here's a hack!
-        if (!result && block.getID() != 0) {
+            if (!result) {
                 server.setBlockType(pt, 0);
                 result = server.setBlockType(pt, block.getID());
             }
@@ -127,6 +128,8 @@ public class EditSession {
                 String[] text = signBlock.getText();
                 server.setSignText(pt, text);
             }
+        }
+        
         return result;
     }
 

src/SMWorldEditListener.java

@@ -92,6 +92,12 @@ public class SMWorldEditListener extends PluginListener {
                                                blockClicked.getY(),
                                                blockClicked.getZ());
 
+                // Bug workaround
+                if (cur.getBlockX() == 0 && cur.getBlockY() == 0
+                        && cur.getBlockZ() == 0) {
+                    return false;
+                }
+
                 try {
                     if (session.getPos1().equals(cur)) {
                         return false;