diff --git a/TODO_Animation.md b/TODO_Animation.md
deleted file mode 100644
index e0b4a7ea..00000000
--- a/TODO_Animation.md
+++ /dev/null
@@ -1,143 +0,0 @@
-## Animation (continuation)
-
-### Goal
-- Provide XML-defined interpolation function
-- Provide new animation API
-
-### Demo
-- Download with round progress bar
-- First X seconds the animation fill the progress bar
-- After that if the downloading is not finished, show a rolling animation
-- When the downloading is finished, show a ending animation
-- Downloaded text fade in
-- Progress bar fly out
-
-### Feature
-
-#### Interpolation function
-A new xml tag will be added in <instance> to write a function:
-- `func <NAME>(start: T, end: T, target: T): IGuiGraphicsAnimationInterpolation^;`
-- `func <NAME>(start: T, end: T, target: U): IGuiGraphicsAnimationInterpolation^;`
-  - if T is a value type so it has to be change a property of type T in U
-
-```
-interface IGuiGraphicsAnimationInterpolation
-{
-    func Interpolate(position: double):void;
-}
-```
-
-#### API
-- A group of new overloading functions are added in `GuiInstanceRootObject` which do
-  - Add animation to `root->GetControlHostInternal()->GetGraphicsHost()->GetAnimationManager()`, where `GetControlHostInternal` is a new protected abstract function.
-  - If the control host is not ready (e.g. the control has not been added to a window), then all animations will be kept and attach to the window later
-  - When the root object is deleted, all animations are stopped (set the internal flag so that the animation manager will remove them later)
-  - And has the following options:
-    - **interpolation object**
-    - **timed or infinite**
-      - for timed animation
-        - **a function** to convert passed total time to a double value
-          - default: `passed total time / total time`
-        - **a fomular** function to convert a double value from `[0..1]` to `[0..1]` to control the animation behavior
-      - for infinite animation
-        - **a function** to convert passed total time to a double value
-          - default: `passed total time`
-    - **end of animation notification**
-      - Stop an `IAsync` object
-      - Call a callback function
-
-#### Workflow
-- Author calls animation APIs themselves to start an animation
-- State machine or async coroutine is supported by "end of animation notification"
-- Add `$Await GetApplication().DoEvents();`
-
-## Proposal (2)
-```xml
-<TimedAnimation Progress="progress"> <!-- Progress's default value is "progress" -->
-  <Interpolation> <!-- Interpolation's default value is "{ return progress; }" -->
-    <!CData[
-      {
-        var pi = 2 * Math::ASin(1);
-        return (Math::Sin((progress - 0.5) * pi) + 1) / 2;
-      }
-    ]]>
-  </Interpolation>
-  
-  <Data Name="Color" Type="Color"/>
-  <Data Name="Distance" Type="int"/> <!-- Data has its own Interpolation child element -->
-  
-  <States Default="A">
-    <State Name="A">
-      <Data Name="Color" Value="#FF0000"/>
-      <Data Name="Distance" Value="0"/>
-    </State>
-    <State Name="B">
-      <Data Name="Color" Value="#FFFFFF"/>
-      <Data Name="Distance" Value="100"/>
-    </State>
-  </States>
-  
-  <!--
-    Generate component:
-      class State{ /* all properties */ }
-      property Current : State^ {const, not observe}
-      property Source : State^ {const, not observe}
-      property Target : State^ {const, not observe}
-      property A : State^ {const, not observe}
-      property B : State^ {const, not observe}
-      func CreateAnimation(source:State^, target:State^, length:int):IGuiGraphicsAnimation^;
-      func ContinueAnimation(source:State^, target:State^, length:int):IGuiGraphicsAnimation^;
-      func GetAnimationLengthScale(source:State^, target:State^, current:State^):double;
-      func Interpolate(source:State^, target:State^, current:State^, progress:double):void;
-  -->
-</TimedAnimation>
-
-<InfiniteAnimation>
-</InfiniteAnimation>
-```
-
-## Proposal (3)
-
-- Remove `<InfiniteAnimation>`
-- Add `Type="Once|Repeat"` to `<TimedAnimation>`
-- All `<State>` should set exactly the same set of properties
-- All properties that are not set in `<State>` should have a `Value` property, which is similar to `Interpolation`
-  - `Property Value` = `Value`(`Interpolation`((`CurrentTime` - `StartTime`) % `Length` / cast double `Length`))
-- (optional) Syntax for `$switch` to wait for callbacks caused from some actions in the `$init` block
-- (optional) Syntax for `$switch` to raise a specified exception for wrong inputs
-
-```
-try
-  {
-    $switch(raise "Sad!")
-    {
-        $init
-        {
-            DownloadAsync().Execute([$1; this.Cancel(); ], null);
-        }
-        case A():{}
-        case B():{}
-    }
-}
-catch(ex)
-{
-    if (ex.Message == "Sad!") { return; }
-    raise;
-}
-```
-
-## Proposal (4)
-
-- Use XML to compose gradient timed animations as building blocks
-- Use coroutine to compose complex animation
-  - **$AwaitTask**: await a task
-  - **$Play**: initiate and await an animation
-  - **$PlayInGroup**: initiate an animation but not wait, a group object (maybe just a number) should be provided
-  - **$AwaitGroup**: await all animations in a group
-  - **$Pause**: wait for several milliseconds
-- If an animation is cancelled, all animations initiated by this animation are cancelled
-- Animation manager object in the control host becomes a animation timer callback
-  - When a root object begins an animation, it attaches the callback object to the manager
-  - When a root object finishes an animation, it detaches the callback object from the manager
-  - When a root object is removed from a control host, it detaches the callback object from the manager, and create a new callback object when it is added to a control host later. Durint the moment, the animation is paused.
-  - Detach an callback object by setting the return value of function "Run" to false, and let the animation manager remove this object later.