Hi there, MariTax. 

I understand how frustrating it can be when some of the client's accounts are not working. I want you to know that I'm here to provide some steps to get Group by dropdown working. 

It could be that you're experiencing a browser-related issue. There are times that the browser is full of frequently accessed page resources, thus causing websites, like QuickBooks Online (QBO), to act weirdly. Try logging into your QBO account using a private browser.

You can use the shortcut keys below:

• Google Chrome: Ctrl + Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Safari: Command + Option + P

If it works, go back to your regular browser and clear its cache. Or else, try using a different supported browser. It could be a temporary issue with QuickBooks and the current browser that you use.

To clear out temporary internet files that might have caused the issue. Use this article as a guide: Clear Cache And Cookies To Fix Issues When Using QuickBooks Online.

For future reference, read through this article: Customize reports in QuickBooks Online. It'll help you learn about personalizing your report to show specific details that are only relevant to you and your business. 

Please know that you're always welcome to swing by anytime if you still have questions or concerns with QuickBooks Online. I'll be around to help. Take care and have a good one.