Bootstrap has such a nice splitbutton UI component. But with some composition you can have a similar component in Vaadin (with the Valo theme) by using the CssLayout and the v-component-group
CSS class.
CssLayout group = new CssLayout(); group.addStyleName("v-component-group"); Button save = new Button("save"); group.addComponent(save); ComboBox box = new ComboBox(); // this puts the icon in the middle of the rest of the combobox box.setWidth("45px"); box.addItem("refresh"); box.addItem("history"); box.addItem("coordinates"); box.setNewItemsAllowed(false); box.setTextInputAllowed(false); group.addComponent(box);
box.setValue(null);