Revert "Add panic detecting underlying bug for issue #16 earlier"

This reverts commit 710b04b.

src/view/selection/tree.rs

@@ -131,10 +131,6 @@ mod imp {
                         if i.selection.document.is_outdated(&info.document) {
                             panic!("selection document was outdated!");
                         }
-
-                        if info.document.is_outdated(&i.selection.document) {
-                            panic!("list item info document was outdated!");
-                        }
 
                         i.selection.path_selected(&info.path)
                     })