Set Up HRMS>Product Related>Global Payroll & Absence Mgmt>Absence Management>Country
Tab: Event Entry

There are three delete options available: 
Delete Option "All Events"
Delete Option "All Events except Processed"
Delete Option "All Events except Finalised"

For example, if delete option "All Events except Finalised" has been selected for a country, the delete button for Absence rows with finalised Absence Events will be inactive.