The Include Items where Vendor is not Preferred checkbox is a sticky feature. To change the preference, follow the steps below:
1. Navigate to Transactions > Inventory > Order Items.
2. Select a specific vendor under the Vendor dropdown.
3. Check or uncheck the Include Items where Vendor is not Preferred checkbox.
4. Reload the Order items page to set back the value of Vendor field to -All-.
The next time the user visits the page, the preference last selected will be shown unless changed.