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
*/
			private Object[] getLimitedChildren(Object[] children) {
				int newLength = MarkerSupportInternalUtilities.getMarkerLimit();
				if (newLength > 0 && newLength < children.length) {
					Object[] newChildren = new Object[newLength];
					System.arraycopy(children, 0, newChildren, 0, newLength);
					return newChildren;
				}
				return children;
			}
			/*
			 * (non-Javadoc)
			 * 
			 * @see org.eclipse.jface.viewers.IStructuredContentProvider#getElements(java.lang.Object)
			 */
			public Object[] getElements(Object inputElement) {
				return getLimitedChildren(((CachedMarkerBuilder) inputElement)
						.getElements());
			}
			/*
			 * (non-Javadoc)
			 * 
			 * @see org.eclipse.jface.viewers.ILazyTreeContentProvider#getParent(java.lang.Object)
			 */
			public Object getParent(Object element) {
				Object parent = ((MarkerItem) element).getParent();
				if (parent == null)
					return builder;
				return parent;
			}