I'm not sure if this bug has been reported before...
If you own lots of IAA compatible apps then Cubasis can't show those further down the alphabet as the list blanks out as you scroll down. It means that the apps further down the alphabet cannot be selected. This happens when adding both instrument apps to audio tracks, and when adding effects apps to the audio or midi tracks. I've noticed that if you click on the blank list then it will open an app, so they are there but just not visible at the end of the list, which means it must be purely a graphics issue.
Also, another thing I've noticed is that with some apps the developers name is displayed in front of the app name. Which means if you have a lot of apps from the same developer you cannot easily decider which app is the one you want as Cubasis displays the developer name first. This doesn't happen with all apps, and it doesn't happen in GarageBand (only the app name is shown) so I figure it's something that can be fixed in Cubasis to just show app names, not proceeded by the developer name.
Example apps that are affected by the naming problem are:
Mini, z3ta+, FunkBox, DXi FM Synthesizer, NLogSynth Pro, Galileo Organ, Magellan, UltraPhaser and AD480 Pro
Hopefully these two things can be fixed!
Ps. Can't wait for 1.8