When tabComponent is set JTabbedPane fires property change event with name "tabComponentAt"
with the index of new tabComponent, that might lead to a problem in the future, because getTabComponentAt(int) returns Component, not an integer

To be on the safe side we need to fire property with another name, just like JTabbedPane.setTitleAt() does.

firePropertyChange("indexForTabComponent", -1, index); would be ok