It is possible to build new buttons as plug-ins for the editor, but I don't think there is any easy way subscribe to the event you want to subscribe to.

What do you want to accomplish?

Over at our code samples page there is a section for editor tools that you might find helpful.

Thanks for your answeere.

What we try to do is to make it possible for an Ediotor entring text in the page to popup a new windows where he can enter keywords that becomes links in the text. Along with the keyword he shoud be able to enter som descriptions for the keyword, that is to be displayed in a small popupbox when the user click on this keyword in the final webside in user mode.

When the editor "push the button" that opens the window described abowe, he is show an alfabetic list of allready defined keyword, and can choose one of them, or make a new one, with the description to be entred to the list. When choosing a keyword from the list, or entring a new one, the keyword should be inserted in the text with a tag that we want to define.