BTW, have you noticed you can also right click on the editor and drag everywhere? Maybe that feature is old, but I only found about it when testing the new Scintilla.
That should be done my the drag/scroll-plugin.
It's probably worth noting that scintilla changebar functionality was added during this time.
The changebar-feature should not be able to affect the mousewheel, but you can try what happens if you disable it with unchecking "Settings -> Editor... -> Margins and caret -> Use changebar".
The part affecting the mousewheelevent in scintilla did also not change with the scintiulla update as far as I know.
If you use a self-compiled C::B it would be interesting to see what happens if the plugins are not even loaded (--safe-mode only disables them).
You can run "make uninstall" to remove all the C::B stuf (the configuration will remain) and use "./configure" without the parameter "--with-contrib-plugins=...".
And maybe you get some usefull error-messages if you change the first line in OnInit() (app.cpp about line 468) from "wxLog::EnableLogging(true);" to "wxLog::EnableLogging(true);" before recompiling (there are some messages that are "normal").
since several days mouse wheel doesn't work any more in editor. It work only if cursor is over scroll bar, which is not comfortable. It also work on other widgets (combobox, ...).
Font size change is also disable if ctrl pressed.
What happens in the ThreadSearch preview window or in the SyntaxHighlighting example window ?
By the way:
It would be of interest if anything else was updated the same time on the systems that have these problems.