Hypersnap 8 and Windows 10

I moved my workstation to Windows 10 (from 7) and now have a delay when capturing a region.   After clicking, there is about a 4 second delay before the cross hairs come up to start your capture.  This is every time it is used, the delay always seems the same.  Extra delay is set at 0 under settings.
 
Windows 10 Pro, i7 8700k, 16GB ddr4
 
Any thoughts on this?

I'm having another problem with Windows 10 Pro version 1903 where I can't install HyperSnap 8 as the default photo viewer. While this may be a known problem setting other programs as the default Photo Viewer program, I'm wondering if anyone has found a solution with, perhaps, a registry tweak. Many thanks for any suggestions.

Admin
In Windows Explorer (a folder) window, right click a .jpg file (or other photo type file), press "Open with ->", "Another program", turn on the option to always use this other program to open this file type and choose HyperSnap 8.

 
Many thanks for the prompt response. I've done this and can get it to open the selected .jpg file with HyperSnap 8, but the setting/selection won't "stick" and defaults back to IrfanView although in the selection of default app for photo viewer there is no program assigned. In other words, if I close HS8 and then double-click on the .jpg file it opens with IV rather than HS8. After selecting HS8 I restarted my Win10 system thinking it might help but with no luck. My next thought is to reinstall HS8 thinking that maybe it is the last program installed which gets to be the default.