This happens a lot, and it depends on the virtual instrument and other factors . . .

THOUGHTS

I use NOTION as a ReWire helper device in ReWire sessions with Studio One Professional 5 as the ReWire host controller . . .

With the exception of Realivox Blue (RealiTone)--my favorite virtual female soprano--all the AUi and VSTi virtual instruments are hosted in Studio One Professional 5 . . .

NOTION has music notation on ReWire MIDI staves, and this is what plays the AUi and VSTi virtual instruments hosted in Studio One Professional 5--except for Realivox Blue, which is hosted directly in NOTION, since it's easier to do the keyswitches that specify the phonetic scripts and other control parameters for her singing . . .

The way longer duration notes and ties behave depends on the specific virtual instrument; and it varies considerably . . .

Some instruments play notes in a specific duration no matter what the actual music notation specifies, where for example the note rings just as long for an eighth note as for a whole note . . .

Other instruments behave the way one expects they should behave . . .

When an instrument note ends abruptly or early and I want it to fade gradually, I tie a set of notes in a long string and then do the fade via an Automation Track in Studio One Professional 5 . . .

This is easy to do once you make sense of Automation in Studio One Professional 5 . . .

Another technique is to use reverberation and an echo unit in Studio One Professional 5 as a way to cause a note to ring or to sustain longer than it would without the reverberation and echo unit . . .

When working with AUi and VSTi virtual instruments, it's matter of the way the virtual instrument engine generates notes, and this depends on the sampled-sounds for the instrument . . .

Some instruments only have one sampled-sound for each note, which typically is short duration . . .

NOTION sends the proper duration request, but what happens is determined by the virtual instrument engine and its sampled sounds . . .

If NOTION requests audio for a whole note but the virtual instrument engine sends the audio for an eighth note or half-note, then this is what NOTION plays, even though the music notation specifies a whole note or a string of tied whole notes . . .

For example, if it's a SampleTank 4 (IK Multimedia) grand piano but the notes do not sustain, then try a different grand piano or try one using MachFive 3 (MOTU), EW ComposerCloud X, Miroslav Philharmonik 2 (IK Multimedia), and so forth . . .

One of the virtual grand pianos will have notes that behave the way you desire . . .

Another strategy is to record the audio onto an Audio Track in Studio One Professional 5 and then to edit the audio . . .

Studio One Professional 5 has tools for editing audio, and this strategy can provide a solution . . .

Audacity has tools for this, as does Melodyne (Celemony) . . .

Audacity

[NOTE: Melodyne Essential is included in Studio One Professional 5. It's a full-featured version of Melodyne; but I have the Melodyne Editor, which has more functions and capabilities . . . ]

Melodyne (Celemony)

Melodyne Versions (Celemony)

Lots of FUN!