This issue was found by our student assistant Cristian...(I'm copying and pasting his Trac bug report here for discussion):
Overview
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With the addition of the new gradebook in moodle 1.9, two new items have been added to the common module settings: ID Number and Grade category.
While cool, the unfortunate side effect of these being added to "common module settings" is that these are able to be filled in even on modules that do not have the ability to be added to the gradebook or graded.
It is also inconsistent from module to module. For example, adding a label does not show either, but link to a file or website shows ID Number and not grade category.
Proposed change
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Remove ID Number and Grade category from common module settings or have some sort of check to see if it's a gradeable module in order to display them.
Looking at the code for the common module settings for "add a label" might help to fix this for modules that cannot be graded
Additional Info
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The modules I've seen have this but cannot be graded are:
Resources
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Compose a text page (has ID number)
Compose a web page (has ID number)
Link to a file or website (has ID number)
Chat
Choice
Wiki
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Thoughts or comments? Thanks!