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diff --git a/app/assets/javascripts/lib/mousetrap.js b/app/assets/javascripts/lib/mousetrap.js
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+++ b/app/assets/javascripts/lib/mousetrap.js
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+// This is the only file allowed to import directly from the package.
+// eslint-disable-next-line no-restricted-imports
+import Mousetrap from 'mousetrap';
+
+const additionalStopCallbacks = [];
+const originalStopCallback = Mousetrap.prototype.stopCallback;
+
+Mousetrap.prototype.stopCallback = function customStopCallback(e, element, combo) {
+  for (const callback of additionalStopCallbacks) {
+    const returnValue = callback.call(this, e, element, combo);
+    if (returnValue !== undefined) return returnValue;
+  }
+
+  return originalStopCallback.call(this, e, element, combo);
+};
+
+/**
+ * Add a stop callback to Mousetrap.
+ *
+ * This allows overriding the default behaviour of Mousetrap#stopCallback,
+ * which is to stop the bound key handler/callback from being called if the key
+ * combo is pressed inside form fields (input, select, textareas, etc). See
+ * https://craig.is/killing/mice#api.stopCallback.
+ *
+ * The stopCallback registered here has the same signature as
+ * Mousetrap#stopCallback, with the one difference being that the callback
+ * should return `undefined` if it has no opinion on whether the current key
+ * combo should be stopped or not, and the next stop callback should be
+ * consulted instead. If a boolean is returned, no other stop callbacks are
+ * called.
+ *
+ * Note: This approach does not always work as expected when coupled with
+ * Mousetrap's pause plugin, which is used for enabling/disabling all keyboard
+ * shortcuts. That plugin assumes it's the first to execute and overwrite
+ * Mousetrap's `stopCallback` method, whereas to work correctly with this, it
+ * must execute last. This is not guaranteed or even attempted.
+ *
+ * To work correctly, we may need to reimplement the pause plugin here.
+ *
+ * @param {(e: Event, element: Element, combo: string) => boolean|undefined}
+ *     stopCallback The additional stop callback function to add to the chain
+ *     of stop callbacks.
+ * @returns {void}
+ */
+export const addStopCallback = (stopCallback) => {
+  // Unshift, since we want to iterate through them in reverse order, so that
+  // the most recently added handler is called first, and the original
+  // stopCallback method is called last.
+  additionalStopCallbacks.unshift(stopCallback);
+};
+
+/**
+ * Clear additionalStopCallbacks. Used only for tests.
+ */
+export const clearStopCallbacksForTests = () => {
+  additionalStopCallbacks.length = 0;
+};
+
+export { Mousetrap };