some of our clients moved to High Sierra. Their solution is hosted on FM16 server, clients are upgraded to FMPro16.
We see a considerable slowdown in some of the portals, and this on both FMPro16 as on FMPro15. This can be reproduced on any machine running HighSierra. All machines still running on Sierra don't have that problem.
We have no clue what is going on. "Randomly" removing some objects make the portal fast again, but we can't point to what can be the cause. Even adding a button can slow down the portal.