This is a screenshot from Opera using FireFly. It clearly illustrates the padding (5px) and margin (0px) of the textbox. However, to the right of the textbox is an unidentified black space of approximately 10px that isn't HTML whitespace, td padding, textbox margin or anything else I can think of.
The spacing also exists in FireFox and IE 9.
(Please ignore the fact that the below button has the same indent - in its case I've added padding-right to the td as a hack to even it out)
Any ideas?