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**Do you want to request a *feature* or report a *bug*?**
A bug

**What is the current behavior?**
When Chrome devtools is highlighting highlight box is shown too small.

![image](https://user-images.githubusercontent.com/44562005/69419027-185ca380-0d5f-11ea-8284-8004147dc713.png)

**What is the expected behavior?**
Highlight box is shown actual template size.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
Chrome 78.0.3904.97
React Developer Tools 4.2.0
initialize();
  }
  const canvasFlow: HTMLCanvasElement = ((canvas: any): HTMLCanvasElement);
  canvasFlow.width = window.screen.availWidth;
  canvasFlow.height = window.screen.availHeight;
  const context = canvasFlow.getContext('2d');
  context.clearRect(0, 0, canvasFlow.width, canvasFlow.height);
  nodeToData.forEach(({count, rect}) => {
    if (rect !== null) {
      const colorIndex = Math.min(COLORS.length - 1, count - 1);
      const color = COLORS[colorIndex];
      drawBorder(context, rect, color);
    }
  });
}
function drawBorder(