Setting the height of the surrounding element refers to the surrounding html tag, the element is within a table so this can be confusing. When you say horizontal, I will assume you mean vertical as you are talking about the height of the table.

Table elements take on the style of the table over the css style sheet. However since Chrome behaves the same way I do not understand the question.

When I define 100% for a table height (table height="100%"), and this table is an INNER table defined within a CELL (this cell is of course defined with a "td", inside a "tr", inside a "tbody/table" for the OUTER table), I expect the height of the INNER table will take on the height of the CELL within wich it is defined (the surrounding element is the cell). But this is not what happens. The height of the INNER table is just dependent on its OWN contents. I use this to try to get HORIZONTAL alignment across INNER tables defined into each cell of one row, defining ONE inner table into each cell (Then to obtain left VERTICAL alignment for items inside each INNER table, defining one row, then several cells, into each of these inner tables). This may seem a little tricky, but this is HOW I NEED it works. But it doesn't. And this is why I use the "valign=top" property for the surrounding cells, in order to align HORIZONTALLY the inner tables (each defined within each cell) of one same row. Now, just checking that Chrome behaves the same way doesn't mean there is no problem, but only that Chrome has the same problem. I hope this will help understand what I think is a problem of compliance with the "height=100%" property.

Best regards