No, the solution should be to disable "readconfig" in the global emulator configuration as I said above. Have you tried it?
That disables everything else in MAME's presets and I only wanted to remove the phosphorescence decay... =\
Or change the preset ini files if you don't like their default values. I cannot handle every possible combination here... for QMC2, the emulator's default value is the one that's printed when you run "mame -noreadconfig -showconfig".
Yeah, I'll just manually edit the ini files since changing a few numbers is no big deal at all. I just thought that it would be possible to disable it from QMC2 since, well, it does say that entering a value of 0 means no decay.
Thanks in any case.