Using mIRC Beta 7.64.6394 on Windows 10 Home, I have encountered a new issue since your last change to try to fix the error reported in this thread.
Thanks for reporting this. Just to confirm: if you run beta 7.64.6125
, the prior beta, do you see this issue?
If you see the issue in 6125, do you see it in any of the previous betas: 7.64.6087 7.64.5829
If you go to the Windows 10 Settings dialog, select System and then About - what Windows specifications (edition, version, etc.) do you see?