Bug 166236 [Viewers] ViewerColumn needs a dispose method
ViewerColumn adds a listener to its label provider which is never removed. We need a dispose method that removes the listener. Furthermore, if the column's label provider wraps a non-column-specific label provider, the viewer is already listening to it and the viewer column shouldn't. Must be fixed before the next I build.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ViewerColumn.java
/**
	 * Return the editing support for the reciever.
	 * 
	 * @return {@link EditingSupport}
	 */
	 EditingSupport getEditingSupport() {
		return editingSupport;
	}
	/**
	 * Set the editing support.
	 * 
	 * @param editingSupport
	 *            The {@link EditingSupport} to set.
	 */
	public void setEditingSupport(EditingSupport editingSupport) {
		this.editingSupport = editingSupport;
	}
	/**
	 * Refresh the cell for the given columnIndex. <strong>NOTE:</strong>the
	 * {@link ViewerCell} provided to this method is no longer valid after this
	 * method returns. Do not cache the cell for future use.
	 * 
	 * @param cell
	 *            {@link ViewerCell}
	 */
	 void refresh(ViewerCell cell) {
		getLabelProvider().update(cell);
	}
}