Get pointers to the selected items
PtGenTreeItem_t **PtGenTreeSelectedItems( PtWidget_t *widget, PtGenTreeItem_t **buffer );
This function fills a buffer with pointers to the currently selected items. If buffer is NULL, the function allocates a buffer using malloc(), and the buffer is NULL-terminated.
If buffer isn't NULL, the function adds a NULL to the end only if there are no selected items.
A pointer to the buffer.