Bug 56491 [Tasks] DeleteCompletedTasks requires Markers to be refreshed
3.0 M8 If you create a new user defined task and mark it completed by clicking on the first column or by using the context menu, the delete completed task actino does not pick up the completed task. However it does work after the markers have been refreshed (eg project rebuild). to test: 1. create a user defined marker, ensuring it is not created as completed 2. click on the first column to mark it as complete 3. select delete completed tasks from the context menu, notice it doesn't pick up the task 4. perform a project re-build (Project|clean...) 5. repeat step 3, it now picks up the marker as complete It looks like the underlying IMarker is being updated, but the concrete TaskMarker is not. The action is looking at the concrete markers.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/MarkerView.java
copyAction.dispose();
		selectAllAction.dispose();
		deleteAction.dispose();
		revealAction.dispose();
		showInNavigatorAction.dispose();
		propertiesAction.dispose();
		clipboard.dispose();
	}
	/* (non-Javadoc)
	 * @see org.eclipse.ui.views.internal.tableview.TableView#createActions()
	 */
	protected void createActions() {
		TableViewer viewer = getViewer();
		revealAction = new ActionRevealMarker(this, getSelectionProvider());
		openAction = new ActionOpenMarker(this, getSelectionProvider());
		copyAction = new ActionCopyMarker(this, getSelectionProvider());
		copyAction.setClipboard(clipboard);
		copyAction.setProperties(getFields());
		pasteAction = new ActionPasteMarker(this, getSelectionProvider());
		pasteAction.setClipboard(clipboard);
		pasteAction.setPastableTypes(getMarkerTypes());
		deleteAction = new ActionRemoveMarker(this, getSelectionProvider());
		selectAllAction = new ActionSelectAll(viewer);
		showInNavigatorAction = new ShowInNavigatorAction(getViewSite().getPage(), getSelectionProvider());
		propertiesAction = new ActionMarkerProperties(this, getSelectionProvider());
		
		super.createActions();
		
		putAction(FILTERS_ACTION_ID, new FiltersAction(this));
	}