See the attached testcase. The square root and fraction bars are visible, while they should be hidden by the mphantom element.
Created attachment 202510 [details] testcase
Created attachment 207396 [details] Patch V1
Comment on attachment 207396 [details] Patch V1 good catch
Comment on attachment 207396 [details] Patch V1 Clearing flags on attachment: 207396 Committed r153088: <http://trac.webkit.org/changeset/153088>
All reviewed patches have been landed. Closing bug.