Table cells don't handle vertical direction properly

[xfq]

This issue is applicable to Japanese, Chinese, Korean, and Mongolian.

If you place the writing-mode property with a value of vertical-rl/lr on an individual table cell in a table that overall has a horizontal direction, you would expect the text in that cell to be displayed vertically, but in some browsers it isn't, unless the height of the td element is specified.

For more details, see this GitHub issue, which is being used to track this gap. Please add any discussion there, and not to this issue.

[xfq]

The first comment in this issue contains text that will automatically appear in one or more gap-analysis documents as a subsection with the same title as this issue. Any edits made to that comment will be immediately available in the Editor's draft of the document. Proposals for changes or discussion of the content can be made by following the link to the GitHub issue being used to track this gap and adding comments there.