Nothing is perfect. I test layouts on current versions of Firefox, Opera, Firefox, Safari, Konqueror, Internet Explorer 6, Internet Explorer 7, and note here discovered inconsistencies.

If you leave size of more than one container in rows udefined, layout may behave strangely in Opera. At best first row will take all available height. At worst it will behave beyond all understanding.

If your layout behaves strangely first thing to check is if your all rows except at most one have size defined.

If you define height (size) of you rows using percentages then:

• in firefox(Gecko), konqueror(KHTML), safari(KHTML) - this means percentage of height of box split into rows
• in opera, ie - this means percentage of height of box split into containers not already occupied by rows with sizes defined in something else then percents

This also affects rows with unspecified sizes since they have size defined as 100% by default.

• Avoid mixing rows with size defined as percentage and rows with size defined using some other units in one rows array.
• Avoid not specifying height of more than one row in one row array and mixing rows with percentage heights with rows with no size specified.
• In some situations you can achieve what you want indirectly by adding additional box nested inside one of containers.

If you define any margins with percentage units very strange behaviour may appear in all browsers, especially ie (from what I saw I guess I should be happy that it doesn't crash totally).

• Avoid using percentage for specifying horizontal and vertical margins of boxes.
• If you need percentage margins then you must specify them with css for html tags placed inside layout.