Button Not Horizontally Aligning in Form

[ls3674]

What property am I missing that will cause the button item to sit in the proper place (to the right of the combobox)?

DynamicForm df = new DynamicForm();
        df.setNumCols(6);
        df.setColWidths("*","*","*","*","*","*");
        df.setWrapItemTitles(false);

df.setItems(new FormItem[]{chkScrollRawLogs,cbiLogType,getButtonItem()});

[Isomorphic]

setStartRow(false), setEndRow(false) (see Form Layout overview).