Alternate text is global on the link picker

I think this is an error prone area.

The alternate text associated with a link remains even when the target changes.

STEPS:
------

• go ahead, start the quickstart and edit articles > myarticle2
• in the Body field select the word body
• click the Internal Link button and select events > myevent1
• in the Title field on the dialog type myevent1
• click OK to close dialog
• click again the Internal Link button and select news > mynews1 in place of events > myevents1
• clcik OK to close that dialog
• click Save and Done to record and release the document
• hover the mouse over the link to news > mynews and notice that it reads myevent1

EXP: when I select a new target the old alternate text should not be carried over
ACT: the dialog keeps the alternate text no matter where the user navigates to