@burnout426 said in can't resize width smaller than 660px after update:

So yeah, it looks like it has changed.

It seems this change was done on purpose starting in Opera 103.0.4906.0 to fix:

DNA-110725 [Address bar] Adress bar buttons and extensions cut when window width is too low

that's listed in https://blogs.opera.com/desktop/changelog-for-103/.