Bug 216811 [Markers] ExtendedMarkersView#setFocus doesn't
The result is that focus is lost if you drag the view to another stack... The most common implementation seems to be 'viewer.getControl().setFocus()... To test: select an element in the Problems or Tasks view. Drag the view to a new location (could be in an existing stack or a new one) notice that while the view is the active view the arrow keys don't navigate...
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/ExtendedMarkersView.java
viewer.getTree().setSortColumn(column);
		if (builder.getSortDirection(field) == MarkerComparator.ASCENDING)
			viewer.getTree().setSortDirection(SWT.UP);
		else
			viewer.getTree().setSortDirection(SWT.DOWN);
	}
	/**
	 * Update the title of the view.
	 */
	void updateTitle() {
		String status = MarkerSupportConstants.EMPTY_STRING;
		int totalCount = builder.getTotalMarkerCount();
		int filteredCount = 0;
		MarkerCategory[] categories = builder.getCategories();
		
		if (categories != null && builder.isShowingHierarchy()) {
			int markerLimit = MarkerSupportInternalUtilities.getMarkerLimit();
			for (int i = 0; i < categories.length; i++) {
				filteredCount += markerLimit < 0 ? categories[i].getTotalSize()
						: Math.min(categories[i].getTotalSize(), markerLimit);
			}
		} else {
			filteredCount = MarkerSupportInternalUtilities.getMarkerLimit();
		}
		if (filteredCount < 0 || filteredCount >= totalCount) {
			status = NLS.bind(MarkerMessages.filter_itemsMessage, new Integer(
					totalCount));
		} else {
			status = NLS.bind(MarkerMessages.filter_matchedMessage,
					new Integer(filteredCount), new Integer(totalCount));