The Query Builder Deck arrangement, size and layout gets saved with your workbook when you save it. If you were last looking at a Subquery Tab when you saved, and you reopen your Query Builder Workbook, that Subquery Tab that will come to focus when you reopen your file. Each time you reopen a Query Builder Workbook it connects to the database you used for its connection and refreshes its contents. If objects you were using in the file were subsequently dropped from the database, red will indicate Invalid Joins or Objects so that you can take action to update your worksheets appropriately. Orange indicates changes could be made, but are not required.