Actions faq:

How to define configurable Shortcut for Component based shortcut?

In order for the action to show up in Keyboards Shortcut dialog you need the action defined in the layer file under "Actions" folder and have the shortcut defined there under "Keymaps/<Profile Name>" linking to your action.

    <folder name="Actions" >
        <folder name="Window">
            <file name="org-netbeans-core-actions-PreviousViewCallbackAction.instance"/>
        </folder>
    </folder>

    <folder name="Keymaps">
        <folder name="NetBeans">
            <file name="S-A-Left.shadow">
                <attr name="originalFile" stringvalue="Actions/Window/org-netbeans-core-actions-PreviousViewCallbackAction.instance"/>
            </file>
        </folder>
    </folder>

The mentioned Action has to be a subclass of org.openide.util.actions.CallbackSystemAction. It does not necessarily has to perform the action, it's just a placeholder for linking the shortcut. You might want to override it's getActionMapKey() and give it a reasonable key.

The actual action that does the work in your component (preferably a simple Swing javax.swing.Action) is to be put into your TopComponent's ActionMap. The key for the ActionMap has to match the key defined in the global action's getActionMapKey() method.

        getActionMap().put("PreviousViewAction", new MyPreviousTabAction());

This way even actions from multiple TopComponents with the same gesture (eg. "switch to next tab") can share the same configurable shortcut.

Note: Don't define your action's shortcut and don't put it into any of the TopComponent's javax.swing.InputMap. Otherwise the component would not pick up the changed shortcut from the global context.