Channel setting does not restore original values after clicking 'Back' button

Reproduction path:

1. Open HAP channel, edit and go to Channel Setting subpage.
2. Change value of a field, e.g., Dropdown color to "Green".
3. Do not click 'Save', click 'Back' to cancel changes and return back to the main edit page.
4. Click 'Edit channel' to open form again.

Expect: the Dropdown color field should restore to the orignal 'White' value.
Actual: 'Green' value is chosen. And the 'Save' button is grey.