Title says it all ;)
If I have checked the "Fewest ingredients first" option, and have a research with only red packs in Deprioritized research, it would be great if other researches were done first even if they require green/blue/other research packs.
Even if I add Prioritized research with other packs, the red-only deprioritized research is done first.

I'll consider it. There may have been a reason why I didn't implement it like this right away, but I can't remember what that reason may have been (or if it's still relevant).

I've implemented this in 2.1.0. Hopefully there was no good reason for the previous implementation.
Still won't completely blacklist the deprioritized technologies (as intended), but it should be far more reluctant to research them, regardless of whether "fewest first" is enabled or not.

Sounds great, I'll try it out this weekend!