create a custom alias field desciption should be hidden by default

Steps:

Go to node/add/webform.
Scroll down and click on URL path settings.
Actually it should not display the "Optionally specify an alternative URL by which this node can be accessed. For example, type "about" when writing an about page. Use a relative path and don't add a trailing slash or the URL alias won't work." text while the "Generate automatic URL alias" is checked.