diff --git a/src/karax.nim b/src/karax.nim
index 85a126a..78395b3 100644
--- a/src/karax.nim
+++ b/src/karax.nim
@@ -135,6 +135,8 @@ proc equalsShallow(a, b: VNode): bool =
       if not equalsShallow(a[i], b[i]): return false
   if not sameAttrs(a, b): return false
   if a.class != b.class: return false
+  if a.track != 0 and b.track != 0:
+    if a.track != b.track: return false
   # XXX test event listeners here?
   return true
 
@@ -191,10 +193,10 @@ proc updateElement(parent, current: Node, newNode, oldNode: VNode) =
         var left = 0
         var rightNew = newLength - 1
         var rightOld = oldLength - 1
-      
+
         while left <= min(rightNew, rightOld):
           var minRight = min(rightOld, rightNew)
-          
+
           while left <= minRight and
               equalsTree(newNode[left], oldNode[left]):
             newNode[left] = oldNode[left]
@@ -205,7 +207,7 @@ proc updateElement(parent, current: Node, newNode, oldNode: VNode) =
             newNode[rightNew] = oldNode[rightOld]
             dec rightOld
             dec rightNew
-          
+
           minRight = min(rightOld, rightNew)
           if left <= minRight:
             updateElement(current, oldNode[left].dom, newNode[left], oldNode[left])
@@ -215,7 +217,7 @@ proc updateElement(parent, current: Node, newNode, oldNode: VNode) =
             updateElement(current, oldNode[rightOld].dom, newNode[rightNew], oldNode[rightOld])
             dec rightNew
             dec rightOld
-        
+
         var posNextElem = rightOld + 1
         var isPushBack = posNextElem == oldLength
         while left <= rightNew:
diff --git a/src/karaxdsl.nim b/src/karaxdsl.nim
index 5ba525a..5553d8f 100644
--- a/src/karaxdsl.nim
+++ b/src/karaxdsl.nim
@@ -4,7 +4,7 @@ from strutils import startsWith, toLowerAscii
 
 const
   StmtContext = ["kout", "inc", "echo", "dec", "!"]
-  SpecialAttrs = ["id", "class", "value", "key"]
+  SpecialAttrs = ["id", "class", "value", "key", "track"]
 
 proc getName(n: NimNode): string =
   case n.kind
diff --git a/src/vdom.nim b/src/vdom.nim
index 48574de..77b3c89 100644
--- a/src/vdom.nim
+++ b/src/vdom.nim
@@ -109,6 +109,7 @@ type
     when false:
       hash*: Hash
       validHash*: bool
+    track*: int
     dom*: Node ## the attached real DOM node. Can be 'nil' if the virtual node
                ## is not part of the virtual DOM anymore.
 
@@ -143,6 +144,8 @@ proc eq*(a, b: VNode): bool =
   if a.attrs.len != b.attrs.len: return false
   for i in 0..<a.attrs.len:
     if a.attrs[i] != b.attrs[i]: return false
+  if a.track != 0 and b.track != 0:
+    if a.track != b.track: return false
   result = true
 
 proc setAttr*(n: VNode; key: cstring; val: cstring = "") =
diff --git a/uibench/nim_uibench.nim b/uibench/nim_uibench.nim
index 3d1f078..55b6456 100644
--- a/uibench/nim_uibench.nim
+++ b/uibench/nim_uibench.nim
@@ -36,7 +36,7 @@ proc createTableCell(id: cstring): VNode =
 
 proc createTableRow(item: TableItemState): VNode =
     let className = if item.active: cstring"TableRow active" else: cstring"TableRow"
-    result = buildHtml(tr(class=className, `data-id` = &item.id)):
+    result = buildHtml(tr(class=className, `data-id` = &item.id, key = item.id)):
         createTableCell("#" & &item.id)
         for i in 0..<len(item.props):
             createTableCell(item.props[i])
@@ -53,7 +53,8 @@ proc createAnimBox(item: AnimBoxState): VNode =
     let color = float(t10) / 10
     let divStyles = cstring"border-radius: " & &t10 &
          "px; background: rgba(0,0,0," & cstring($color) & ")"
-    result = flatHtml(tdiv(class="AnimBox", `data-id` = &item.id, style=divStyles))
+    result = flatHtml(tdiv(class="AnimBox", `data-id` = &item.id, key = item.id,
+        style=divStyles))
 
 proc animCreateVNode(data: AnimState): VNode =
     result = buildHtml(tdiv(class="Anim")):