diff --git a/app.tsx b/app.tsx
index 12c0a66..f582e7e 100644
--- a/app.tsx
+++ b/app.tsx
@@ -1,7 +1,7 @@
 import React from "react";
 import * as Iso from "@eno/iso";
 import Collapse, {CollapseButton, CollapseGroup} from "$/collapse.tsx";
-import C from "./context.tsx";
+import * as C from "./context.tsx";
 
 const Comp = React.lazy(()=>import("./deep/component.tsx"));
 
@@ -22,7 +22,30 @@ export default ()=>
             </Collapse>
         </header>
         
-        <C/>
+        <C.Group>
+            <C.Button></C.Button>
+            <C.Menu>
+                <p>hello!</p>
+                <p>hello!</p>
+                <p>hello!</p>
+                <p>hello!</p>
+                <C.Group>
+                    <C.Button></C.Button>
+                    <C.Menu>
+                        <p>hello!</p>
+                        <p>hello!</p>
+                        <p>hello!</p>
+                        <p>hello!</p>
+                        <p>hello!</p>
+                        <p>hello!</p>
+                        <p>hello!</p>
+                    </C.Menu>
+                </C.Group>
+                <p>hello!</p>
+                <p>hello!</p>
+                <p>hello!</p>
+            </C.Menu>
+        </C.Group>
 
         <main class="layout-middle">
         <Iso.Switch>
diff --git a/context.tsx b/context.tsx
index a8e848e..52e8d92 100644
--- a/context.tsx
+++ b/context.tsx
@@ -1,5 +1,4 @@
 import React from "react";
-import { CollapseControls, Collapser } from "./components/collapse.tsx";
 
 type StateArgs = {done?:boolean, open?:boolean};
 type StateObj = {done:boolean, open:boolean};
@@ -7,52 +6,82 @@ type StateBinding = [state:StateObj, update:(args:StateArgs)=>void];
 
 const CTX = React.createContext([{done:true, open:false}, (args)=>{}] as StateBinding);
 
-export default ()=>
+export const Group =(props:{children:React.JSX.Element|React.JSX.Element[]})=>
 {
     const [stateGet, stateSet] = React.useState({done:true, open:false} as StateObj);
-    const setter =(args:StateArgs)=> stateSet({...stateGet, ...args});
+    return <CTX.Provider value={[stateGet, (args:StateArgs)=> stateSet({...stateGet, ...args})]}>{props.children}</CTX.Provider>;
+};
 
-    return <CTX.Provider value={[stateGet, setter]}>
-        <Inner/>
-    </CTX.Provider>;
-}
-
-const Inner =()=>
+export const Menu =(props:{children:React.JSX.Element|React.JSX.Element[]})=>
 {
     const [stateGet, stateSet] = React.useContext(CTX);
     const refElement:React.MutableRefObject<HTMLElement|null> = React.useRef( null );
     const refControl:React.MutableRefObject<CollapseControls|null> = React.useRef( null );
 
-    React.useEffect(()=>
-    {
-        refControl.current = Collapser(refElement.current as HTMLElement, true);
-    }
-    , []);
+    React.useEffect(()=>refControl.current = Collapser(refElement.current as HTMLElement, true), []);
+    React.useEffect(()=> {refControl.current && refControl.current(stateGet.open, 1000, ()=>stateSet({done:true}))}, [stateGet.open])
 
-    React.useEffect(()=>
-    {
-        console.log("open changed to:", stateGet.open);
-        refControl.current && refControl.current(stateGet.open, 1000, ()=>stateSet({done:true}));
+    return <div ref={refElement as React.Ref<HTMLDivElement>}>{props.children}</div>;
+};
 
-    }, [stateGet.open])
-
-    React.useEffect(()=>{
-        console.log("done changed to:", stateGet.done);
-    }, [stateGet.done])
-
-    return <div class="p-4">
+export const Button =()=>
+{
+    const [stateGet, stateSet] = React.useContext(CTX);
+    return <>
         <p>{JSON.stringify(stateGet)}</p>
         <button class="px-10 py-2 bg-red-500 text-white" onClick={e=>stateSet({open:true,  done:false})}>Open</button>
         <button class="px-10 py-2 bg-red-500 text-white" onClick={e=>stateSet({open:false, done:false})}>Close</button>
-        <div ref={refElement as React.Ref<HTMLDivElement>}>
-            <p>hello</p>
-            <p>hello</p>
-            <p>hello</p>
-            <p>hello</p>
-            <p>hello</p>
-            <p>hello</p>
-            <p>hello</p>
-        </div>
-    </div>;
-
+    </>;
 };
+
+type DoneCallback =(openState:boolean)=>void;
+export type CollapseControls =(inOpen?:boolean, inMs?:number, inDone?:DoneCallback)=>void;
+export function Collapser(inElement:HTMLElement, initialState = false)
+{
+    let userDone:DoneCallback = (openState) => {};
+    let userMode = initialState;
+    let frameRequest = 0;
+
+    const done = (inEvent:TransitionEvent)=>
+    {
+      if (inEvent.propertyName == "height" && inEvent.target == inElement)
+      {
+        inEvent.stopPropagation();
+        if (userMode)
+        {
+          inElement.style.height = "auto";
+          inElement.style.overflow = "visible";
+        }
+        userDone(userMode);
+      }
+    };
+    inElement.addEventListener("transitionend", done);
+
+    return function(inOpen, inMs, inDone)
+    {
+      cancelAnimationFrame(frameRequest);
+
+      if(arguments.length)
+      {
+        userDone = inDone|| ((m)=>{}) as DoneCallback;
+        userMode = inOpen === true;
+
+        inElement.style.height = inElement.clientHeight + "px";
+        inElement.style.overflow = "hidden";
+        inElement.style.transition = "none";
+        frameRequest = requestAnimationFrame(()=>
+        {
+          inElement.style.transition = `height ${(inMs||1000) / 1000}s`;
+          frameRequest = requestAnimationFrame(()=>
+          {
+            inElement.style.height = `${inOpen ? inElement.scrollHeight : 0}px`;
+          });
+          
+        });
+      }
+      else
+      {
+        inElement.removeEventListener("transitionend", done);
+      }
+    } as CollapseControls;
+}
\ No newline at end of file