Bug 281126 [CSS] Illegal state exc from tab-height
If you just type a space in the CSS Editors SWT example you will get traces in the console failing on CSSValue.getFloatValue() for tab-height.
bundles/org.eclipse.e4.ui.css.core/src/org/eclipse/e4/ui/css/core/impl/dom/Measure.java
case LexicalUnit.SAC_STRING_VALUE:
			return CSS_STRING;
		case LexicalUnit.SAC_OPERATOR_COMMA:
			return CSS_CUSTOM;  
		}
		
		throw new UnsupportedOperationException("NOT YET IMPLEMENTED - LexicalUnit type: " + value.getLexicalUnitType());
	}
	
	/*
	 * (non-Javadoc)
	 * @see org.w3c.dom.css.CSSValue#getCssText()
	 */
	public String getCssText() {
		switch (value.getLexicalUnitType()) {
		case LexicalUnit.SAC_INTEGER:
			return String.valueOf(value.getIntegerValue());
		case LexicalUnit.SAC_REAL:
			return String.valueOf(value.getFloatValue());
		case LexicalUnit.SAC_PERCENTAGE:
		case LexicalUnit.SAC_PIXEL:
		case LexicalUnit.SAC_CENTIMETER:
		case LexicalUnit.SAC_EM:
		case LexicalUnit.SAC_INCH:
			return String.valueOf(value.getFloatValue()) + value.getDimensionUnitText();
		}
		return value.getStringValue();
	}
}