toolbar button to undo last step

src/App/BottomPanel.tsx

@@ -1,10 +1,22 @@
+import { useEffect, useState } from "react";
 import { TraceableError } from "../statecharts/parser";
 
 import "./BottomPanel.css";
 
 export function BottomPanel(props: {errors: TraceableError[]}) {
-  return <div className="toolbar">
-    <div className="errorStatus">{
-      props.errors.length>0 && <>{props.errors.length} errors {props.errors.map(({message})=>message).join(',')}</>}</div>
+  const [greeting, setGreeting] = useState("Welcome to StateBuddy, buddy!");
+
+  useEffect(() => {
+    setTimeout(() => {
+      setGreeting("");
+    }, 2000);
+  }, []);
+
+  return <div className="toolbar bottom">
+    <>{greeting}</>
+    {props.errors.length > 0 &&
+      <div className="errorStatus">
+        {props.errors.length>0 && <>{props.errors.length} errors: {props.errors.map(({message})=>message).join(', ')}</>}
+      </div>}
   </div>;
 }