Still frustrated by the slow selection tool. None of the options suggested so far seem to be applicable to my situation, however I do seem to have discovered a work around which will probably be OK for 'amateurs' like myself, although the professionals won't like it, I suspect.
To begin at the beginning, I have a 2year old 64bit Lenovo Ideacentre, with on-board Intel HD Graphics ( no other designation number). SU Checkup tells me my system is fine for SU2017 but I have the unbearable lag on selection tool. My Windows 10 system updated to 1706 on 6th June and I installed SU for the first time a couple of days later. When I check Windows Update, none of the Updates mentioned in this thread are shown as having been installed and I suspect that the 1706 upgrade incorporated them all as part of the consolidated build. Since it took 2 hours for the upgrade to install and so far I've found no other problems with it, rolling back to the 1607 version is not a viable option to me, especially since I would presumably then have the problem of the culprit update continually trying to re-install itself.
I have seen various suggestions that using SU 2016 solves the problem, but that isn't strictly true, in my case at least. I have installed SU 2016Make, 64bit version, to see what happens, and found the lag is still there. I then went even further back and installed SU 2015Make, 64bit version, but again the lag is still there.
I then had a flash of inspiration, removed the SU 2016 64Bit and installed SU 2016 32Bit instead and, lo and behold, it seems to be fine!
So whatever the underlying problem is, it appears to be affecting a difference between 32 and 64 Bit versions of SketchUp.
As I say, this is unlikely to be satisfactory for the professionals, but it seems to work for us lesser mortals who don't necessarily need the finest bells and whistles..