Hi, Niklas1.

I appreciate you getting back to us. Allow me to help you further with adjusting the report's column width (Journal Report) in QuickBooks Online.

Have you tried out the steps provided by my peer above, like clearing the browser's cache? I've tried adjusting columns in my Journal Report in QuickBooks Online and was able to adjust it.

To better isolate the issue, as an additional step, we can press the F5 key on your keyboard to refresh the page.

If you're still unable to adjust the column width on your Journal Report, I'd suggest getting in touch with our QuickBooks Online Support. Unlike in this public forum, they have the tools required to perform any escalations in the system whenever necessary on your behalf. To ensure we address your concern on time, check out our support hours.

I recommend customizing the report to get the specific details you need. You can also memorize it to save its current customization settings. It serves as your record and helps you quickly access it for future use. 

If there's anything else I can help you with, please let me know. I'm always here to help you out.