I write the same parameters as described in manual in the beginning of the diagram:
skinparam sequenceGroupingFontSize 30
skinparam sequenceGroupingHeaderFontSize 30
but the sizes remain too small and don't change. What do i do wrong?
UPD: I think it is important to mention, that skinparam sequenceArrowFontSize 20 and skinparam sequenceParticipantFontSize 17 do work.