There are lots of issues with High DPI monitors. Notepad++ tries to be “DPI Aware” and many of the features around this are new to Windows. Could be that a related change is not backward compatible with Windows 7.

Generally the blurry area is rendered by Scintilla and not by Notepad++ itself. And Scintilla has its own DPI challenges.

Do you use custom DPI for the OS? Does it make a difference if you change it?

If you run Notepad++ from a shortcut, enter its properties and observe compatibility tab. There aren’t as many settings as newer Windows but there is still High DPI related settings that may make a difference.

See if enabling/disabling Notepad++ option “Use DirectWrite” makes a difference.

Try playing with your video adapter properties, enabling/disabling 2D optimizations, even if you wouldn’t want to change it permanently, it could help identify the problem area.

I keep Notepad++ updated to the latest version whenever I’m prompted that one is available. I also forgot to mention that this happens with any font.

Although I have realized that there is at least one other app that suffers from this same issue; so it can’t be Notepad++

I’ve also discovered that if I launch Notepad++ immediately after start-up it doesn’t happen. So, I’m beginning to at least collect some clues.

Considering that Windows 7 is 10+ years since it’s last release, and nearly 2 years past the end of its extended support, I’m not sure that anyone will be able to replicate your problem

I know at least one person who still uses Windows 7, but he doesn’t have this problem.
Hmm … I like talking about him in the third person.
Gives everything a noble touch - maybe I should stick with that. :-)

Sorry, never seen such a thing.

With TextFX installed, I am wondering how old your Notepad++ is – because most people don’t have that installed anymore. (?-menu’s Debug Info would tell us that, and other useful information; and, btw, if your Notepad++ is old enough that it doesn’t have the Debug Info entry in the ? menu, that’s telling you something right there.)

Maybe you have a weird plugin (again, you didn’t show us ? menu’s Debug Info, which would have told us).

Or maybe you’ve got a strange font, or some other application running that is intentionally blurring things.

Considering that Windows 7 is 10+ years since it’s last release, and nearly 2 years past the end of its extended support, I’m not sure that anyone will be able to replicate your problem, or do more than wild guesses as to your difficulty.