Idea Summary
The "Workspace ID" on the APEX “Create Workspace” administration page (app 4050, page 27, item F4050_P27_SECURITY_GROUP_ID) is defined as a Number. But javascript does not consider really big numbers to be numbers. 
https://oracleapex.com/ is currently assigning Workspace IDs that are bigger than what javascript allows as a number. Hence it is (nearly) impossible to create a workspace that has the same Workspace ID as a recently created workspace on https://oracleapex.com/.

Of course, this could be true in customer installations as well. Though, admittedly, this is unlikely.

Use Case
It's no longer critical because we can export and import components into different workspaces. But it has long been a best practice to have the same workspace ID in DEV, TEST, PRODUCTION. Maybe it is not longer a valid concern.

Preferred Solution (Optional)
Make the F4050_P27_SECURITY_GROUP_ID a text field and handle the validations as a server side validation.