Hello, this is because Firefox 57 is more optimized for WebExtensions. Firefox 52 ESR was back when Firefox had more support for old XUL based 'legacy' add-ons.

Thank you Mkll, I know firefox ESR supports legacy addons, but I think it should supports WebExtension too and it did (other parts of my addons works as expected only create window return 'createData is null' ) Maybe it's a bug in browser.window.create API, maybe i should report it as a bug on bugzilla

When Firefox 52 ESR was released not all all the new API's needed for WebExtensions were completed. Version by version the new API's were added, and the older API's were deprecated.

bmossavari said

Maybe it's a bug in browser.window.create API, maybe i should report it as a bug on bugzilla

Have you tested it in Firefox 57? Don't report it as a bug if it works in 57.

What happens if you pass an empty object:

var creating = browser.windows.create({}); 

Not that you should have to, just wondering whether Firefox is looking for something in particular and that might provide a more helpful error message.

For reference: https://developer.mozilla.org/Add-ons/WebExtensions/API/windows/create

More generally, there is extension developer support over here:

https://discourse.mozilla.org/c/add-ons/development

This forum focuses on end-user issues.

Thank you jscher2000 for clarification

jscher2000 said

What happens if you pass an empty object: var creating = browser.windows.create({}); Not that you should have to, just wondering whether Firefox is looking for something in particular and that might provide a more helpful error message. For reference: https://developer.mozilla.org/Add-ons/WebExtensions/API/windows/create

passing empty object did the trick