Bug 275171 [Contributions] Customize Perspective action breaks editor pinning action
Using M7, I enabled editor pinning (i.e. Reuse editor) and pinned an editor using an action in the toolbar. I then disabled editor pinning ad then opened the customized perspective dialog. After this, enabling/disabling editor pinning does not make the Pin Editor action reappear.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/WorkbenchActionBuilder.java
showViewMenuAction = null;
        showPartPaneMenuAction = null;
        nextPartAction = null;
        prevPartAction = null;
        nextEditorAction = null;
        prevEditorAction = null;
        nextPerspectiveAction = null;
        prevPerspectiveAction = null;
        activateEditorAction = null;
        maximizePartAction = null;
        minimizePartAction = null;
        switchToEditorAction = null;
        quickAccessAction.dispose();
        quickAccessAction = null;
        backwardHistoryAction = null;
        forwardHistoryAction = null;
        undoAction = null;
        redoAction = null;
        quitAction = null;
        goIntoAction = null;
        backAction = null;
        forwardAction = null;
        upAction = null;
        nextAction = null;
        previousAction = null;
        openWorkspaceAction = null;
        projectPropertyDialogAction = null;
        newWizardAction = null;
        newWizardDropDownAction = null;
        importResourcesAction = null;