In order for CompanyDB, BudgetID, Object, and Account Number (Budget Account Number) data to be available for Lookup, the "InLookup" box needs to be respectively checked on Manage Company Databases, Manage Budgets, Manage Objects, and Manage Budgets Accounts.
Below is an example of a Lookup Search screen.
Please note it can be a useful tool to limit the number of available CompanyDBs, BudgetIDs, Objects and Account Numbers in their respective Search dropdown menus to only those that are necessary by unchecking the "InLookups" boxes as this can result in a "decluttered" search dropdown menu.
Below Actuals 2015 and 2016 were selected while the 2014 Forecast and others were not.
Below Actuals 2015 and 2016 appear in the Search dropdown menu while 2014 Forecast and others do not.
Related Article/s:
How Do I Add/Delete Budget IDs that are Available in Lookups