Show template error in preview

If there is an error in a template, you only get to know which line and column the error is on, and not the actual error. To find that, you need to go to the logs.

It would be nice if the error would show in the preview as well. It would also be nice if the preview window didn’t scroll horizontally with an error inside.

Example:

Hi @lassejl!

This is clearly a bug and I have added it to our issue tracker.

This is fixed in a previous release.