silverstripe-framework/admin/scss/ie7.scss

html {
	overflow: hidden;
}

.field {
	input.text, 
	textarea,
	.TreeDropdownField {
		// Left/right padding conflicts with 100% width on the element unless box-sizing is respected, so disable padding for IE
		padding-left: 0;
		padding-right: 0;
	}
}