On my Samsung Chromebook Plus and Chromebook Pro, the new v13 UI simply does not work well. This has been true ever since v13.0 came out, and is no different in 13.1.

Most dropdown boxes simply do not work, and can not be selected via mouse click. Some, but not all, can be selected via touchscreen. For those that can't be selected via touchscreen, you simply can't select at all.

Example:
Click APPS with mouse - that works correctly.

Then...
Click DEFAULT POLICY with mouse - that does not work. Clicking it does nothing.
Touch DEFAULT POLICY with finger on touchscreen - that works correctly.

Then...
Touching a specific rack in the rack drop down list - that does not work.
Clicking a specific rack in the rack drop down list - that does work.