TStrings.EndUpdate

Each time you modify the string list, for example, add new strings or change them, the component which holds the given string list is repainted. You can use the BeginUpdate method before making changes to the string list in order to suspend repainting the component holding the given string list until the changes are complete. To resume painting the component, call the EndUpdate method after the changes are complete. This approach optimizes performance and can prevent the component from blinking during modifying a large number of items.