When Webkit encounters an inline-block where...
1. the line-height height is explicitly specified
2. the content is rendered using multiple line-boxes
...the inline-block element ignores the specified vertical-align. I've linked to my test case to help illustrate the problem.
1. Create a block-level element
2. Create a inline-block element as a child of the block created in Step 1.
3. Set the `vertical-align` of the inline-block to "middle"
4. Fill the inline-block with enough content so that the inline-box for that content extends horizontally beyond bounds of the containing block-level element
5. Set the `line-height` of the inline-block. Use a value smaller than the `line-height` value of the containing block.
The vertical-align property of the inline-block is ignored.
The inline-block treats `vertical-align` in the same manner as other inline elements
Tested on 2010-05-18 in Mac OS 10.6 using Safari 4.0.5 (6531.22.7) and Google Chrome 5.0.375.38 beta
just ran into this bug, and can confirm that it does happen as described. ironically, adding a single non-breaking space as a sibling to the inline-block item will correct this behavior.