Index of the last visible (in window) item, or -1 if the document is empty.
property LastItemVisible: Integer;
You can use this property (for example, in OnVScrolled event handler) to get the index of the last visible item.
This property does not take horizontal scrolling into account, only vertical one.
Note: returning value of this property requires some calculations; so if you need to use it several times in the same procedure, assign its value to some temporary variable and then use this variable.
See also properties: