Remove the old unused tooltip code

src/App.css

 .App {
   text-align: center;
 }
-
-.tooltip {
-    position: absolute;
-    display: inline-block;
-    border-bottom: 1px dotted black; /* If you want dots under the hoverable text */
-    z-index: 10;
-}
-
-.tooltip .tooltiptext {
-    visibility: hidden;
-    width: 120px;
-    background-color: black;
-    color: #fff;
-    text-align: center;
-    padding: 5px 0;
-    border-radius: 6px;
-
-    position: absolute;
-}

src/PointMap.js

@@ -7,8 +7,6 @@ import CardActions from '@material-ui/core/CardActions';
 import Button from '@material-ui/core/Button';
 import Typography from '@material-ui/core/Typography';
 
-import Tooltip from './Tooltip.js';
-
 const polygon_size = 0.01
 const polygon_size_lat = polygon_size * 2
 const polygon_size_lon = polygon_size
@@ -31,20 +29,6 @@ class PointMap extends Component {
     this.state = { viewport, mouseover, clicked };
   }
 
-  update_tooltip(visible, x, y, content) {
-    this.setState((prevState) => {
-      let tooltipVisible = visible;
-      y -= 20;
-      x += 10;
-      let tooltip = {x, y, content};
-      return {
-        ...prevState,
-        tooltipVisible,
-        tooltip,
-      };
-    });
-  }
-
   handleOnHover(e) {
     this.setState(prevState => {
       let mouseover = null;
@@ -213,7 +197,6 @@ class PointMap extends Component {
             viewState={this.state.viewport}
           />
         </DeckGL>
-        {this.state.tooltipVisible && <Tooltip {...this.state.tooltip} />}
         { this.state.clicked &&
             this.getCard(this.state.clicked)
         }

src/Tooltip.js

-import React from 'react';
-
-export default function Tooltip({ x, y, content }) {
-  return (
-    <div className="tooltip" style={{left: x, top: y}}>
-      <div>{content}</div>
-    </div>
-  );
-};