browser.devtools.panels.elements.createSidebarPane not working on Nightly

I’ve followed the documentation to create browser.devtools.panels.elements.createSidebarPane with setObject.
I want to set custom html element in my pane like Rules, Fonts in DOM and Style Inspector panel.

Browser: Nightly 63.0a1 (2018-08-08) (32-bit)

Expected result:

  • It should show pane with the JSON object defined

Actual result:

  • It shows a blank screen pane.