I click "New Data Comparison" (or "New Schema Comparison"), then ALT-W to open the "Database Connection Properties" dialog, then TAB to get into the "Server" input box. Once there, I type a part of the name of the server and the list of available servers works nicely!

It seems that I must use down DOWN ARROW to select the server from the list and press ENTER before I can get out.

However, if I type the entire server name, I can't get out of that box! Pressing TAB or ENTER does nothing.