The "populate" button in the new recipe creation window is meant to fill recipe values automatically, however it is currently broken. When giving an external URL the window hangs without nothing happening. When giving local file as src, the button doesn't seem to do anything. I am aware of previous bugs about this, but those were solved saying the "remote functionality" was removed. I still see this button on this window and it is still failing. So the issue here is to fix it or remove the button.
Bitbake Commander was deprecated in 2.1 and is no longer supported. In fact, it is being dropped from the build [YOCTO #10032]. If the community would like to submit patches to fix this, please re-open the bug.