diff --git a/manual/plugins.rst b/manual/plugins.rst
index 35e5c8594a..11f4a29fea 100644
--- a/manual/plugins.rst
+++ b/manual/plugins.rst
@@ -153,7 +153,7 @@ from its bases, documented below. A typical basic USBMS based driver looks like
    :members:
    :member-order: bysource
 
-User Interface actions
+User interface actions
 --------------------------
 
 If you are adding your own plugin in a ZIP file, you should subclass both InterfaceActionBase and InterfaceAction. The
diff --git a/src/pyj/read_book/mathjax.pyj b/src/pyj/read_book/mathjax.pyj
index 533c9f60da..eb27093dcf 100644
--- a/src/pyj/read_book/mathjax.pyj
+++ b/src/pyj/read_book/mathjax.pyj
@@ -50,6 +50,8 @@ def apply_mathjax(mathjax_files, link_uid, proceed):
         if not standalone_proceed_data.event_listender_added:
             standalone_proceed_data.event_listender_added = True
             document.documentElement.addEventListener("calibre-mathjax-typeset-done", standalone_proceed)
+        if standalone_proceed_data.proceed:
+            print('MathJax apply called while a previous apply is still running')
         standalone_proceed_data.link_uid = link_uid
         standalone_proceed_data.proceed = proceed
         load_mathjax(f'{runtime.FAKE_PROTOCOL}://{runtime.SANDBOX_HOST}/mathjax/startup.js')