You actually can't edit RealTracks or RealDrums in that way. RealTracks and RealDrums are actual "audio recordings" of live performances by musicians.

Some of these have also been manually transcribed to show the relevant notation of the performance, but making changes to that does not reflect back to adjust the pre-recorded audio.

In later versions, you can substitute MIDI in place of RealTracks/RealDrums in parts, but not in the version you have.

I hope this explains why your changes are not being saved.

BIAB & RB2025 Win.(Audiophile), Sonar Platinum, Cakewalk by Bandlab, Izotope Prod.Bundle, Roland RD-1000, Synthogy Ivory, Kontakt, Focusrite 18i20, KetronSD2, NS40M Monitors, Pioneer Active Monitors, AKG K271 Studio H'phones