Bug 171415 [Viewers] Table viewer needs to clear label, image when items are reused
If an item is reused for a different element on a refresh, the table viewer needs to clear the label and image from the item being reused. This is necessary to communicate to the label provider that a new label is needed (i.e. the label provider may defer providing a label if decorators are not ready). This is what the tree viewer does. To see the problem, open the Java Browsing perspective and select a Java project. Then click between different packages. Notice that some of the labels in the Types list take a while to update. Opening one of these reveals that the label is showing the wrong text.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTableViewer.java
* programmer, this method will throw ERROR_INVALID_RANGE despite the fact
	 * that a single column of data may be visible in the table. This occurs
	 * when the programmer uses the table like a list, adding items but never
	 * creating a column.
	 * 
	 * @param index
	 *            the index of the column to return
	 * @return the column at the given index
	 * @exception IllegalArgumentException -
	 *                if the index is not between 0 and the number of elements
	 *                in the list minus 1 (inclusive)
	 * 
	 * @since 3.3
	 */
	protected abstract Widget doGetColumn(int index);
	/**
	 * Returns the item at the given, zero-relative index in the receiver.
	 * Throws an exception if the index is out of range.
	 * 
	 * @param index
	 *            the index of the item to return
	 * @return the item at the given index
	 * @exception IllegalArgumentException -
	 *                if the index is not between 0 and the number of elements
	 *                in the list minus 1 (inclusive)
	 * 
	 * @since 3.3
	 */
	protected abstract Item doGetItem(int index);
	/**