Bad display with HorizontalSplitPanel

Hello
I’m new with Vaadin.
I want to include an HorizontalSplitPanel into a CSSLayout with others components. My class extends CssLayout and is set into the window (setContent).
Here the result :

As we can see, the left label ‘test’ is not displayed. The splitter is out of the layout.
My class is

import com.vaadin.ui.CssLayout;
import com.vaadin.ui.HorizontalSplitPanel;
import com.vaadin.ui.Label;
import com.vaadin.ui.themes.Reindeer;

public class AccordionTest extends CssLayout {

	private static final long serialVersionUID = -774249641877178680L;

	public AccordionTest() {
		
		addStyleName("form");
		
		Label accordionTitle = new Label("TEST");
		accordionTitle.addStyleName("form-title");
		addComponent(accordionTitle);
		
		Label progression = new Label("Progess: ");
		progression.addStyleName("form-progress");
		addComponent(progression);
		
		Label motifSelectionHeader = new Label("Selection:");
		motifSelectionHeader.addStyleName("form-select");
		addComponent(motifSelectionHeader);
		
		HorizontalSplitPanel motifSelection = new HorizontalSplitPanel();
		motifSelection.setStyleName(Reindeer.SPLITPANEL_SMALL);
		motifSelection.addStyleName("form-select-split-content");

		Label l1 = new Label("test");
		motifSelection.setFirstComponent(l1);
		
		Label l2 = new Label("test");
		motifSelection.setSecondComponent(l2);

		addComponent(motifSelection);
	}
}

My CSS file contains

.form {
	position: absolute;
	overflow: visible;
	top: 400px;
	left: 20px;
	width: 800px;
	height: 300px;
	border: 1px solid #cccccc;
}
.form-title {
	height: 20px;
	background: #cccccc;
	color: white;
	font-weight: bold;
	width: 800px;
}
.form-progress {
	height: 20px;
	width: 800px;
	background: #dddddd;
}
.form-select {
	height: 20px;
	background: #cccccc;
	color: #df0000;
	font-weight: bold;
	width: 800px;
}
.formu-select-split-content {
	height: 150px;
}

After searchs on Google and Vaadin book, I have no idea.
I have no special error when I analyze with Vaadin Debug Window (Layouts analyzed on server, total top level problems: 0 ).

Can you help me ?

Many thanks.

OK
After some hours I have found the error : a bad height for the split. Solution is to let 100% height un split css and set SIZE_UNDEFINED in code.
Solution works with IE or Safari but split is not displayed with FF.
Thanks