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
/*
			 * (non-Javadoc)
			 * 
			 * @see org.eclipse.ui.IPartListener2#partBroughtToTop(org.eclipse.ui.IWorkbenchPartReference)
			 */
			public void partBroughtToTop(IWorkbenchPartReference partRef) {
				
			}
			/*
			 * (non-Javadoc)
			 * 
			 * @see org.eclipse.ui.IPartListener2#partClosed(org.eclipse.ui.IWorkbenchPartReference)
			 */
			public void partClosed(IWorkbenchPartReference partRef) {
				
			}
			/*
			 * (non-Javadoc)
			 * 
			 * @see org.eclipse.ui.IPartListener2#partDeactivated(org.eclipse.ui.IWorkbenchPartReference)
			 */
			public void partDeactivated(IWorkbenchPartReference partRef) {
				
			}
			/*
			 * (non-Javadoc)
			 * 
			 * @see org.eclipse.ui.IPartListener2#partHidden(org.eclipse.ui.IWorkbenchPartReference)
			 */
			public void partHidden(IWorkbenchPartReference partRef) {