Run-in issue
Test cases
http://test.csswg.org/suites/css2.1/20110111/html4/run-in-breaking-002.htm http://test.csswg.org/suites/css2.1/20110111/html4/run-in-contains-inline-003.htm http://test.csswg.org/suites/css2.1/20110111/html4/run-in-abspos-between-002.htm http://test.csswg.org/suites/css2.1/20110111/html4/run-in-contains-table-caption-001.htm http://test.csswg.org/suites/css2.1/20110111/html4/run-in-contains-table-cell-001.htm http://test.csswg.org/suites/css2.1/20110111/html4/run-in-contains-table-row-001.htm http://test.csswg.org/suites/css2.1/20110111/html4/run-in-contains-table-row-group-001.htm
Discussion
Recommend that we mark this part of the spec undefined. Only trident passes and no other vendor plans to implement in the short term.