This is not a bug, it's more of a style issue, but if a modal form is set to open in Small, Smaller, Smallest the red X (close) button is placed outside from the modal "window".
If you want it in place (like i do) use this css code:
If you want it in place (like i do) use this css code:
.small i, .tiny i, .mini i {
top: 10px!important;
right: 10px!important;
}