Fix some issues with disabled edit fields.

tests/browser-disabled-fields.html

@@ -0,0 +1,14 @@
+<!doctype html><title>Cthulhu Browser Probe</title>
+<p>Before fields</p>
+<div tabindex="0" aria-label="Completed row" onclick="">
+<div><input autofocus id="answer" aria-label="Answer" value="Solved"></div>
+<div><input id="readonly" aria-label="Read only answer" value="Confirmed" readonly></div>
+</div>
+<input type="password" aria-label="Secret" value="Private fixture">
+<p>After fields</p>
+<script>document.addEventListener('keydown', e => {
+if (e.key === 'F9') {
+  document.getElementById('answer').disabled = true;
+  document.getElementById('readonly').disabled = true;
+}
+});</script>