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

src/EditSession.java

@@ -113,20 +113,23 @@ public class EditSession {
      */
     private boolean rawSetBlock(Vector pt, BaseBlock block) {
         boolean result = server.setBlockType(pt, block.getID());
-        // 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) {
-            server.setBlockType(pt, 0);
-            result = server.setBlockType(pt, block.getID());
-        }
-        server.setBlockData(pt, block.getData());
+        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) {
+                server.setBlockType(pt, 0);
+                result = server.setBlockType(pt, block.getID());
+            }
+            server.setBlockData(pt, block.getData());
 
-        // Signs
-        if (block instanceof SignBlock) {
-            SignBlock signBlock = (SignBlock)block;
-            String[] text = signBlock.getText();
-            server.setSignText(pt, text);
+            // Signs
+            if (block instanceof SignBlock) {
+                SignBlock signBlock = (SignBlock)block;
+                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;