Hello there, @PoolHero1. 

The right part of your estimates is a collapsable tab that shows the Customer's info and transactions related to him. It's a helpful feature that helps you with your transactions.

Since the past problem appeared again, let's fix this by following the troubleshooting steps below:

1. Close QuickBooks.
2. Open the QuickBooks Toolhub.
3. In the QuickBooks Tool Hub, select Program Problems
4. Select Quick Fix my Program.
5. Start QuickBooks Desktop and open your data file.

Open your QuickBooks and see if the space on the estimate returns to being a normal tab. If the problem continues, you can refer to this link and proceed to Solution 2.

Here's an article on solving common errors in the program: Fix common problems and errors with the QuickBooks Desktop Tool Hub.

When you need clarification on QBDT or creating transactions, know that we're always here to help. Keep us updated and stay safe!