Lots of Eclipse 3.X RCP application which switched to Eclipse 4 as runtime complained that they get the QuickAccess search bar of the Eclipse IDE for “free”.
Thanks to René Brandstetter for solving Bug 411821 this does not happen automatically anymore.
In case you want to use the QuickAccess box in your Eclipse 3.X you have to add it as model fragment similar to the LegacyIDE_fragment.e4xmi fragment in the org.eclipse.ui.ide.application plug-in. You can see the details also in the commit. The nice thing is that you can add it at a position you select, e.g. the status line or the toolbar.
Thanks to René for solving this long outstanding issue, which prevented some 3.X RCP applications to use the Eclipse 4 runtime.