I have a case on Windows 7, IE10 when grid is working fine with default Windows font settings, however when I change the Windows Font Size to Medium then go to grid and add a second row then the first row become invisible unless you click arrow up
Please see the attachment for screenshots.
My grid fonts are defined as
div.pq-grid *{
font-family:Arial ,sans-serif;
font-size:12px;
color:black;
}