Error output of dev-client is not selectable in Firefox/Windows

[janpio]

Short description of the problem:

It is impossible to Ctrl+A the whole text of a Error page like this one in Firefox on Windows:

Only the stack trace is selectable.

What behavior are you expecting?

Ctrl+A works as expected. Users don't have to post screenshots of the error messages in the forum and here in issues.

Steps to reproduce:

1. Break your project.
2. Run ionic serve on Windows 10 with default browser Firefox 53

Which @ionic/app-scripts version are you using?

1.3.0