combo box listener?

I have a Main Frame that have JTabbed Pane with 3 tabs. These tabs are constructed entirely in separate classes. The first tab(say 'A') have a JComboBox which have items like Tab B and Tab C.

When Main Frame is loaded or program start Tab A is only enabled while tab 'B', tab 'C' is disabled. When user select item, like 'Tab B' from combo box then Tab B should be enabled.

So problem is, which Listener to use such that, Main Frame can catch event triggered due to index change from comboBox.

-Note:Main Frame just calls the tab method and holds it in panel.

ActionListener