According to http://www.w3.org/TR/REC-CSS2/tables.html#q7
The height of a 'table-row' element's box is calculated once the user agent has all the cells in the row available: it is the maximum of the row's specified 'height' and the minimum height (MIN) required by the cells.
Load the attached sample & press the button - tr disappears, though it clearly had a height assigned.
Mozilla has the intended behaviour - tr has its height.
Created attachment 16207 [details]
A test case
Test case attached
Note that if the TR's style attribute is specified in markup (rather then set after parsing), the test case behaves as expected.
*** This bug has been marked as a duplicate of bug 24971 ***