What is a Drop Indicator ?

The subject name says all:

What is a Drop Indicator ?

On Windows for example you see an ARROW Symbol beside your (to be dropped) Object instead of a STOP Symbol, while you drag.

That’s true if the drag operation is “Move,” but other operations have different cursors. Typically there are four different modes:
0. None (the cursor has a stop symbol)
0. Copy (has a + next to the cursor)
0. Move (just the arrow cursor)
0. Alias (cursor has a curly arrow next to it)

Currently in Xojo Desktop, only the user can control the modes, by pressing modifier keys while they drag. On Web, you can specify the viable operations for both the source and destination objects from which only the overlapping modes are allowed. If there are still more than one option, the operation is up to the user.

Thank you guys.

I found that in the ListBox (http://documentation.xojo.com/api/deprecated/listbox.html#listbox-dropindicatorvisible).

This surprise me. The explanation was very short (contrary to Greg’s answer which is very good).