[Rd] Problem with accessibility in R 4.2.0 and 4.2.1.

[Andrew Hart]

Hi. I'm having an issue with R 4.2.1 on Windows but I'm not sure if this 
is the right place to ask about it. If it's not, I'm hoping someone can 
point me in the right direction.

I'm blind and have been using R for about 11 years now. The base build 
available on CRAN is quite accessible and works pretty well with 
screen-reading software such as JAWS for Windows and NVDA. R-studio is 
not accessible which appears to have something to do with the version of 
QT it uses, but that's not relevant as I don't use it.

Recently I installed R 4.2.1 (I tend to upgrade two or three times a 
year and this time I was jumping from R 4.1.2 to 4.2.1).
However, I've encountered a serious problem which makes the latest 
version more or less unusable for doing any kind of serious work.
The issue is that the screen-reading software is unable to locate the R 
cursor and behaves as though the cursor is near the top left of the R 
application window. Practically, this means I can't tell what characters 
I'm passing over when cursoring left and right, nor can I hear what 
character is being deleted when the backspace is pressed. Most 
importantly, I can't tell where the insertion point is. This is a major 
regression in the ability to work with and edit the command line in the 
R console. There are ways of actually viewing the command line but the 
way I work is frequently calling up a previous command and making a 
change so as to not have to type the whole command again.

I Went and installed R 4.1.3 and R 4.2.0 in an attempt to find out 
exactly when things went awry and the issue first appeared in R 4.2.0.
Looking through the release notes, the only things mentioned that seem 
likely to be relevant are the following:

• R uses a new 64-bit Tcl/Tk bundle. The previous 32-bit/64-bit bundle 
had a different layout and can no longer be used.

and

• R uses UTF-8 as the native encoding on recent Windows systems (at 
least Windows 10 version 1903, Windows Server 2022 or Windows Server 
1903). As a part
of this change, R uses UCRT as the C runtime. UCRT should be installed 
manually on systems older than Windows 10 or Windows Server 2016 before 
installing
R.

I can't really see how changing to utf-8 as the native encoding would 
produce the behaviour I'm seeing, so I am guessing that the change in 
TCL/TK might be the culprit.

I'm hoping that someone will be able to help shed some light on what's 
going on here.

Thanks a lot,
Andrew.