fixup! fixup! Bug 27476: Implement about:torconnect captive portal within Tor Browser

Bug 41526: revert removal of focus to cancle button + add prevention
from keyboard input to trigger multiple buttons as focus switches

browser/components/torconnect/content/aboutTorConnect.js

@@ -517,6 +517,9 @@ class AboutTorConnect {
       this.hide(this.elements.viewLogButton);
     }
     this.show(this.elements.cancelButton, true);
+    if (state.StateChanged) {
+      this.elements.cancelButton.focus();
+    }
   }
 
   showOffline(error) {
@@ -772,6 +775,28 @@ class AboutTorConnect {
         this.beginAutoBootstrap(value);
       }
     });
+
+    // Delay the "Enter" activation of the given button from "keydown" to
+    // "keyup".
+    //
+    // Without this, holding down Enter will continue to trigger the button
+    // until the user stops holding. This means that a user can accidentally
+    // re-trigger a button several times. This is particularly bad when the
+    // focus gets moved to a new button, and the new button can get triggered
+    // immediately. E.g. when the "Connect" button is triggered it disappears
+    // and focus moves to the "Cancel" button.
+    for (const button of document.body.querySelectorAll("button")) {
+      button.addEventListener("keydown", event => {
+        if (event.key === "Enter") {
+          event.preventDefault();
+        }
+      });
+      button.addEventListener("keyup", event => {
+        if (event.key === "Enter") {
+          button.click();
+        }
+      });
+    }
   }
 
   initObservers() {