durationProvider = createDurationValueProvider();
durationProvider.addObserver(this);
// The main label provider for the first column:
CompositeCellLabelProvider mainLabels = new CompositeCellLabelProvider(
new PerspectiveLabelProvider(),
new DateLabelProvider(),
new WorkspaceStorageLabelProvider());
// The viewer:
filteredTree = Viewers.newFilteredTree(parent,