GoLand slowness

I have been using Gogland trial version for 6 months and it's brilliant.  Recently I had to upgrade to the next trial version. (Nov 30 version #GO-173.3727.144).  To get Go programs to build this also required me to upgrade to Go 1.9.  Since then many things are annoyingly slow. Particularly annoying is that the red squiggles take forever to disappear once the code is correct.  I find myself staring at code for half a minute or more trying to work out what is wrong with it - then the squiggles disappear because it was OK all along. (Previously this error-checking process was almost instant.)  It also takes a lot longer to build and run.  IDE generally also seems sluggish now at times.

Is this a problem with GoLand or is Go 1.9 much slower? The machine is not the problem (Windows 10, 64GB RAM, SSD drives). I was going to buy GoLand soon but having 2nd thoughts.