Universal Audio UAD Plug-Ins ver.7.4.2 - Manual (Page 408)

UAD Powered Plug-Ins Manual - 408 - Chapter 40: RealVerb Pro
When in Morphing mode ( Figure 130 on page 408 ), non user-adjustable con
trols will change their appearance and will no longer be accessible. When in
serted on a Send effect, the ‘W’ button automatically turns on (to keep the mix
at 100% wet).
On an insert effect, the Mix will change back and forth between the two mix
values of each preset.
Figure 130. RealVerb Pro in Morphing mode