There was talk about this back in the day.
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Select one note
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Switch to Split tool.
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Position tool where you want and click. Split at that point. (for our purposes, say in the exact middle.)
Now…
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Select a bunch of notes
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Switch to Split tool.
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Position tool at the first note… again in the middle of the note and hit Ctrl Click.
All selected notes are split at the middle (the spot you pointed at).
It would work the same way for multiple selections of Events and Parts.
Maybe this got implemented at some point. If not, I’d use this a LOT.