There is a CSS style bug with the Widget LabelField:

FieldLabel and Text were not rendered on the same base line. Causer is a different paddingTop-Value in CSS definition for class ".x-form-item-label" (LabelField) and class "x-form-label" (Text)

gxt-all.css (Line 1246)
.x-form-item-label {
clear: left;
display: block;
float: left;
padding: 3px 3px 3px 0;
position: relative;
width: 100px;
z-index: 2;


}


gxt-all.css (Line 1568)
.x-form-label {
font-size: 12px;
padding: 2px 3px 3px 0;


}