Need a scrolling panel (or customer class) for column selection SuggestPopup

[scottdear]

The column selection does not present a scroll bar. This could be solved in CSS if the column suggestpopup had a different class than the value selection, then I could add

.gwt-SuggestBoxPopup-custom .suggestPopupContent {
height: 300px;
overflow-y: scroll;
}

[scottdear]

I made a pull request w/ the change to make the above work, I added a class to the suggestPopup so it can be styled uniquely from the other suggestPopup. on commit 74fa5b7