FLStudio 12, there is one problem that has arisen that wasn't there in FL 11.
I encounter this problem through using Kontakt but it will apply to any plugin that uses multiple MIDI-Out channels that are routed ...
FLStudio includes a wide range of plugins: generators, tools and effects. However most of these are FLStudio format only. Which means they only work in FLStudio.
If they are available as a VST or AU format ...