Do you mean that the Bank Account won't hold at the top of the Deposit screen, or is it one of the Accounts assigned under Add funds to this deposit? If you're clicking an account to select it from the list but it still doesn't appear in the field, it's possible your browser's local cache files are causing interruptions in QuickBooks Online (QBO).
Web-based platforms like QBO collect cache files (cookies) to save you time when loading repetitive data and images. These files can often become outdated or corrupted, causing issues like the one with your Bank Deposit. Clearing them out may allow you to properly select the account, and here's how you can do so in all supported browsers:
By doing this, you'll force QuickBooks to load a new version of the Account boxes in the Deposit screen, which will help you properly make a selection. Please don't hesitate to reach out to me here for all of your QuickBooks needs, I want to ensure your success. Thanks for dropping in and have a magnificent rest of your week.