We use a Tridion 2013 environment and with two schema we recently have issues. In the past we were able create/edit components using these schema without issues.
Now if we open existing components or try to create new ones with the schema the input form is not displayed correctly in Content Explorer, so we are not able to edit the fields. Only the labels of the fields are displayed, but there is no edit field anymore.
Also if we do changes to the components and save and close them the changes are not saved. So if we reopen the components the changes are gone. We have this issue with different Firefox and IE versions.
One of the schema was changed 2 days ago, but also rolling back to an older schema did not fix the problem.