Summary

Currently the 'Configure fields' configuration on the create/edit issue screen is a global configuration (on the user end). If a user hides field A on project 1, field A will be hidden as well on project 2.

Changing the feature to be project specific will eliminate problems where user gets 'required field' error but they forgot that they have actually hidden the field. Since the 'Configure fields' button is not exactly very visible, it's pretty common for users to forget that it exist or they have actually hidden some fields.