Bug 95672 Focus changes slow when java browsing perspective open
To reproduce: 1. Run Eclipse in your favorite profiler 2. Open the Java browsing perspective 3. Profile the time taken to switch between java editors On my system, approx. 50% of the time is spent in JavaBrowsingPart.partBroughtToTop. Notice that this method continues to dominate activation changes, even when another perspective is active and no java browsing parts are visible.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/browsing/JavaBrowsingPart.java
if (selection == null || selection.isEmpty()) {
			
			input= getSite().getPage().getInput();
			if (!(input instanceof IJavaElement)) {
				if (input instanceof IAdaptable)
					input= ((IAdaptable)input).getAdapter(IJavaElement.class);
				else
					return;
			}
			selection= new StructuredSelection(input);
		}
		selectionChanged(null, selection);
	}
	/**
	 * Returns the context ID for the Help system
	 *
	 * @return	the string used as ID for the Help context
	 */
	abstract protected String getHelpContextId();
	/**
	 * Returns the preference key for the link to editor setting.
	 *
	 * @return	the string used as key into the preference store
	 */
	abstract protected String getLinkToEditorKey();
	/**
	 * Adds additional listeners to this view.
	 * This method can be overridden but should
	 * call super.
	 */