bug#42350: 26.3; C-c C-c in R console buffer causes Control key to get "stuck"

[Mark Seeto <markseeto@gmail.com>]

On Thu, Jul 16, 2020 at 6:30 PM Eli Zaretskii <eliz@gnu.org> wrote:
> Can you please send detailed instructions for how to reproduce this with Python?  I have Python installed, but I don't use it interactively, so I will need detailed step by step instructions.  Including, if needed, installation of add ons.

For this to work I think you need to have your Python directory in
your Windows path. I have the elpy package installed but as far as I
know, the instructions below don't depend on it.

At the Windows command prompt in the Emacs 26.3 bin directory:
emacs -Q <return>

Start Python:
M-x run-python <return>

Go to the Python console buffer:
C-x o

Using the right Control key:
C-c C-c <return>

For me, this produces the message "<C-return> is undefined", which
doesn't happen if the C-c C-c <return> is entered using the left
Control key. If further keys are pressed, the result is as though a
Control key is being held down.

Press the left Control key to go back to normal.

In Emacs 25.3.1, M-x run-python produces a warning, but once I go to
the Python console buffer, the problem described above doesn't happen.

Thanks.