diff --git a/src/elements.zig b/src/elements.zig
index 3db04a1..fb1ad68 100644
--- a/src/elements.zig
+++ b/src/elements.zig
@@ -92,7 +92,17 @@ pub fn Tree(App: type) type {
                     this.scrollback = 0;
                     this.idx = 0;
                 },
-                // TODO also support key inputs to change the current file?
+                .key => |key| {
+                   if (key.eql(.{ .cp = 'J' }) and this.idx < this.len - 1) {
+                       this.idx += 1;
+                       this.queue.push(.{ .file = this.idx });
+                   }
+
+                   if (key.eql(.{ .cp = 'K' }) and this.idx > 0) {
+                       this.idx -= 1;
+                       this.queue.push(.{ .file = this.idx });
+                   }
+                },
                 .mouse => |mouse| if (this.len > 0) switch (mouse.button) {
                     .left => if (mouse.y + this.scrollback < this.len) {
                         this.idx = mouse.y + this.scrollback;
diff --git a/src/main.zig b/src/main.zig
index 0bc3986..45e3bac 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -46,13 +46,23 @@ pub fn main() !void {
     var element_root: tui_diff.elements.Root(App) = .init(allocator);
     var element_tree: tui_diff.elements.Tree(App) = .init(&app.queue);
 
+    // NOTE hold change set as entries of the changes for each file of in the `App.Model.changes`
+    var change_set: std.ArrayList([]tui_diff.elements.Change(App)) = .empty;
+    defer {
+        for (change_set.items) |change| allocator.free(change);
+        change_set.deinit(allocator);
+    }
+
     var iter = app.model.changes.iterator();
     var entry = iter.next();
     while (entry != null) : (entry = iter.next()) if (entry) |e| {
         var changes = try allocator.alloc(tui_diff.elements.Change(App), e.value_ptr.items.len);
         for (0.., e.value_ptr.items) |i, diff_index|
             changes[i] = .init(diff_index);
+        // `tui_diff.elements.Diff` does not own the changes array because it only passes the
+        // corresponding `Element` instances for the `Container` tree generation
         try element_root.diffs.append(allocator, try tui_diff.elements.Diff(App, allocator, changes));
+        try change_set.append(allocator, changes);
     };
 
     var root = try tui_diff.Container(App, allocator, &element_root, &element_tree);