getting started with the `hydra' package from GNU Elpa -- fail with simplest example

[nljlistbox2@gmail.com (N. Jackson)]

Hello everyone,

Is this a suitable list for getting help with the `hydra' package
from GNU Elpa?

If not, can anyone point me to the right list?

I am running the current version of `hydra', 0.14.0, installed
(from GNU Elpa using the Emacs package manager) for the first time
today.

I'm trying to run the simplest example from the readme file for
the package [1]. I take the following steps:

0. $ emacs -Q

1. M-x package-initialize RET

2. In *scratch* type the example code from the readme:

(defhydra hydra-zoom (global-map "<f2>")
  "zoom"
  ("g" text-scale-increase "in")
  ("l" text-scale-decrease "out"))

3. C-x C-e to evaluate it

4. Hit F2 to run it

Expected behaviour:

A prompt is displayed listing `g' and `l' as possible keys;
pressing 'g' or `l' changes the font size; pressing any other key
exits the hydra.

Observed behaviour:

No prompt is displayed. Only "f2-" is displayed in the echo area.
Pressing `g' or `l' changes font size as expected and _after_
pressing either `g' or `l' at least once, a hydra prompt is
displayed and subsequently pressing any other key exits the hydra
as expected. However, if a key other than `g' of `l' is pressed
before either `g' or `l' is pressed an error message is displayed.
E.g. pressing `n' produces

  <f2> n is undefined

After the error message is printed, text typed in the buffer at
point is coloured red. [Presumably text properties or an overlay
that was meant to go in the minibuffer were applied at point.]

Any help or pointers would be much appreciated.

Thanks.
N.

[1] <https://github.com/abo-abo/hydra#sample-hydras>