diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 21ce58748..afcfeb89d 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -2,9 +2,12 @@ name: Empress CI
 
 # Controls when the action will run. 
 on:
-  # Triggers the workflow on pull request events but only on the master branch
+  # Triggers the workflow on pull request and push events, only on the master
+  # branch
   pull_request:
     branches: [ master ]
+  push:
+    branches: [ master ]
 
 jobs:
   # name of job
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 95cb8672c..35815b52e 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -17,8 +17,8 @@ npm install -g qunit-puppeteer jshint prettier@2.0.5
 
 If you don't have `npm` installed, you will need to install that first.
 
-**Note**: if you can't install puppeteer, the test suite can be run using a
-web browser by opening the page in `tests/index.html`.
+**Note**: if you can't install puppeteer, the (JavaScript) test suite can be
+run using a web browser by opening the page in `tests/index.html`.
 
 ## Running tests
 
@@ -34,6 +34,17 @@ make test
 If you just want to run the Python or JavaScript tests, you can run
 `make pytest` or `make jstest` respectively.
 
+### Notes about JavaScript tests
+If you add HTML elements to EMPress' HTML code that the JavaScript code relies
+on, you will also need to add these elements to the `tests/index.html` file.
+Ideally this would not be necessary, but for now it is. (Failing to do this can
+cause obscure error messages from the JS tests.)
+
+Also, loading the test `index.html` fails on Firefox for some of the `Legend`
+tests: see https://github.com/biocore/empress/issues/435. To circumvent this,
+if you need to load the tests in the browser (rather than using puppeteer),
+we recommend using a different browser for the time being.
+
 ## Front-end development
 
 For convenience, a utility script `./tests/python/make-dev-page.py` is bundled