Bug 278091 [CSS] Measure.getCssText() with float value results in IllegalStateException
In theory we should be able to provide percentages as part of the gradients, e.g. CTabFolder:selected { background-color: #FF0000 #0000FF 30% } But this generates IllegalStateException calling getCSSText() on org.apache.batik.css.parser.CSSLexicalUnit$FloatLexicalUnit from Measure.getCSSText().
tests/org.eclipse.e4.ui.tests.css.swt/src/org/eclipse/e4/ui/tests/css/swt/GradientTest.java
static final RGB BLUE = new RGB(0, 0, 255);
	static final RGB WHITE = new RGB(255, 255, 255);
	static public CSSEngine engine;
	
	protected CTabFolder createTestCTabFolder(String styleSheet) {
		Display display = Display.getDefault();
		engine = createEngine(styleSheet, display);
		
		Shell shell = new Shell(display, SWT.SHELL_TRIM);
		FillLayout layout = new FillLayout();
		shell.setLayout(layout);
		Composite panel = new Composite(shell, SWT.NONE);
		panel.setLayout(new FillLayout());
		CTabFolder folderToTest = new CTabFolder(panel, SWT.NONE);
		CTabItem tab1 = new CTabItem(folderToTest, SWT.NONE);
		tab1.setText("A TAB ITEM");
		
		engine.applyStyles(folderToTest, true);
		shell.pack();
		return folderToTest;
	}
	
	public void testGradients() throws Exception {
		CTabFolder folderToTest = createTestCTabFolder(
				"CTabFolder:selected { background-color: #FF0000 #0000FF}");
		assertEquals(RED, getSelectionBackgroundBegin(folderToTest).getRGB()); 		
		assertEquals(BLUE, folderToTest.getSelectionBackground().getRGB()); 
	}
	
	public void testDefaultPercents() throws Exception {