You can't change the amount to be allocated directly. This amount changes each time you make an entry in the Account Opening Balances window. Generally speaking, as you enter amounts for asset accounts, the amount left to be allocated rises; when you enter amounts for liability and equity accounts, the allocation amount decreases. (This is because of the accounting principle which states that assets must equal liabilities and equity.)

The amount to be allocated will fluctuate as you make entries. When you've made entries for all your accounts, though, the amount should be zero. (That is, there is nothing more to be allocated.) If you close the Account Opening Balances before the allocation amount is zero, that amount will be transferred to your Historical Balancing account.

This tip applies to:

Account Opening Balances window