[ HasEmitter ]
public signal void selection_changed (uint position, uint n_items)
Emitted when the selection state of some of the items in model changes.
Note that this signal does not specify the new selection state of the items, they need to be queried manually. It is also not necessary for a model to change the selection state of any of the items in the selection model, though it would be rather useless to emit such a signal.
::: warning Note that you have to be careful when modifying the model in signal handlers, as it may cause reentrancy problems. This is also the case when you modify base models underneath the selection model. When in doubt, defer changes to an idle.
| position |
The first item that may have changed |
| n_items |
number of items with changes |