this is not something that can be achieved with just css. the issue is that the week grid is being created by superimposing two tables together, both with no background, therefore giving the impression of a grid, but not a true grid. the lengthwise portion of the grid is the higher z-index, so it will always appear on top, and therefore no hover event will ever fire for the height. I played around with ways to trick the user in to seeing the box as highlighted, however, without the ability to know where you are vertically in the grid, it's not really possible. it may be something that could be done with jquery, but i would think the effort involved would not be worth it.