Do not clear tree_states when loading ids

The tree state must be set after loading ids but we can rely on the stored
state.

issue10366
review361811002

src/screen.js

@@ -1291,7 +1291,6 @@
             if (set_cursor === undefined) {
                 set_cursor = true;
             }
-            this.tree_states = {};
             this.tree_states_done = [];
             this.group.load(ids, modified);
             if (ids.length && this.current_view.view_type != 'calendar') {