selected text is not visible when it is errored in red.

**Describe the bug**
When an error is there in the code, we can't see the selected text.
**To Reproduce**
Steps to reproduce the behaviour:
1. Go to 'AST explorer' - https://astexplorer.net/, have 'Espree' as parser with Transform 'Eslint v4'. ( I think it would be reproducible for all other options too.)
2. Write
`const {promisify as foo} = require('util');`

3. It will become red in colour due to error, not select the whole text, you will realize that the selected text isn't visible, but it is actually getting selected behind the scene as clicking backspace deletes the selected text.

**Expected behavior**
A clear and concise description of what you expected to happen.
It should be visible to the user.

**Browser (please complete the following information):**
- OS: Ubuntu Bionic
- Browser Google Chrome
- Version 73