On the TC creation and editing page, if you put a value in an optional field you can not remove it. On the creation page, say I put a value in for the name or description and try to save but the save fails (as when the script is missing), then if I remove the values for the description or name, correct the problem, and try to save again-the removed values get saved. The same thing happens if I try to change the values to an empty string, through the editing page.
Same problem also occurs with TPs, if I try to remove the description of a TP through the editting page, the description remains unchanged.
(I am also unable to edit the name of the TP--I thought that we could edit that field--but this is a different issue.)
Same problem with TRV edit for the description and additional notes fields and for the name and derived-from field for the TR.
Basically, the problem seems to exist for all the string type fields.
I tried testing this by removing the description field on a TPV. After I hit save, I shown a window that is "bad". It has no header and no value for the ID field. The name field is still populated.