Interactive grid shuttle column shuttle size

Hi,

I need help I have interactive grid that has one column defined as Shuttle type.

The problem is that shuttle dialog window width is bigger then the region itself.

I would like to remove the white part where the red arrow is:

Currently I have this inline CSS on the page but it only applies to two shuttle select columns.

.apex-item-group--shuttle {
width: 30%;
border-collapse: collapse;
}
.shuttleSelect1 select, .shuttleSelect2 select {
max-width: 300pt;
}