In the Renoise Matrix panel, using “CTRL + ALT + mouse wheel rotation” allows you to zoom horizontally of the Matrix.
If you use Windows 11 Magnifier, it seems that this control is stolen by Windows 11 Magnifier, so it doesn’t work, even if Renoise is in the foreground…
That’s perfectly fine IMHO. The magnifier overrides this shortcut globally - for all, or at least most, applications. That’s how it’s supposed to work?