Index: src/insert.c
==================================================================
--- src/insert.c
+++ src/insert.c
@@ -1908,11 +1908,13 @@
   }
   for(i=0; i<pDest->nCol; i++){
     Column *pDestCol = &pDest->aCol[i];
     Column *pSrcCol = &pSrc->aCol[i];
 #ifdef SQLITE_ENABLE_HIDDEN_COLUMNS
-    if( (pDestCol->colFlags | pSrcCol->colFlags) & COLFLAG_HIDDEN ){
+    if( (db->flags & SQLITE_Vacuum)==0 
+     && (pDestCol->colFlags | pSrcCol->colFlags) & COLFLAG_HIDDEN 
+    ){
       return 0;    /* Neither table may have __hidden__ columns */
     }
 #endif
     if( pDestCol->affinity!=pSrcCol->affinity ){
       return 0;    /* Affinity must be the same on all columns */

Index: test/hidden.test
==================================================================
--- test/hidden.test
+++ test/hidden.test
@@ -96,6 +96,58 @@
 
 do_execsql_test 3.2.3 {
   SELECT __hidden__a FROM t5;
 } {{} {} {}}
 
+
+do_execsql_test 3.3.1 {
+  CREATE TABLE t5a(a, b, __hidden__c);
+  CREATE TABLE t6a(a, b, __hidden__c);
+  INSERT INTO t6a(a, b, __hidden__c) VALUES(1, 2, 3);
+  INSERT INTO t6a(a, b, __hidden__c) VALUES(4, 5, 6);
+  INSERT INTO t6a(a, b, __hidden__c) VALUES(7, 8, 9);
+}
+
+do_execsql_test 3.3.2 {
+  INSERT INTO t5a SELECT * FROM t6a;
+  SELECT * FROM t5a;
+} {1 2   4 5   7 8}
+
+do_execsql_test 3.3.3 {
+  SELECT __hidden__c FROM t5a;
+} {{} {} {}}
+
+do_execsql_test 3.4.1 {
+  CREATE TABLE t5b(a, __hidden__b, c);
+  CREATE TABLE t6b(a, b, __hidden__c);
+  INSERT INTO t6b(a, b, __hidden__c) VALUES(1, 2, 3);
+  INSERT INTO t6b(a, b, __hidden__c) VALUES(4, 5, 6);
+  INSERT INTO t6b(a, b, __hidden__c) VALUES(7, 8, 9);
+}
+
+do_execsql_test 3.4.2 {
+  INSERT INTO t5b SELECT * FROM t6b;
+  SELECT * FROM t5b;
+} {1 2   4 5   7 8}
+
+do_execsql_test 3.4.3 {
+  SELECT __hidden__b FROM t5b;
+} {{} {} {}}
+
+#-------------------------------------------------------------------------
+# Test VACUUM
+#
+reset_db
+do_execsql_test 4.1 {
+  CREATE TABLE t1(a, __hidden__b, c UNIQUE);
+  INSERT INTO t1(a, __hidden__b, c) VALUES(1, 2, 3);
+  INSERT INTO t1(a, __hidden__b, c) VALUES(4, 5, 6);
+  INSERT INTO t1(a, __hidden__b, c) VALUES(7, 8, 9);
+  DELETE FROM t1 WHERE __hidden__b = 5;
+  SELECT rowid, a, __hidden__b, c FROM t1;
+} {1 1 2 3   3 7 8 9}
+do_execsql_test 4.2 {
+  VACUUM;
+  SELECT rowid, a, __hidden__b, c FROM t1;
+} {1 1 2 3   3 7 8 9}
+
 finish_test