I discovered that the drum sounds were mapped to timbres. But for the preset drums of the OPL series, if I do not set ADSR and TL, only use the default parameters, and set "DrumSetEnhanced", I find that I will not be able to audition such drum sounds, because when I click the FM register, the ToneType will Automatically changes to Custom (0), this should be a bug.
I discovered that the drum sounds were mapped to timbres. But for the preset drums of the OPL series, if I do not set ADSR and TL, only use the default parameters, and set "DrumSetEnhanced", I find that I will not be able to audition such drum sounds, because when I click the FM register, the ToneType will Automatically changes to Custom (0), this should be a bug.