Issue 6113 - Improve reliability of "block element" dialog

lib/filterComposer.js

Index: lib/filterComposer.js
diff --git a/lib/filterComposer.js b/lib/filterComposer.js
index fe6d51eb9b0bb32f0fc574dced0c2b81a39a3352..d16a0b826730a600bd94e8634c9b5211675c4b21 100644
--- a/lib/filterComposer.js
+++ b/lib/filterComposer.js
@@ -238,20 +238,26 @@ port.on("composer.openDialog", (message, sender) =>
     let doInit = () =>
     {
       doInitAttempt += 1;
-      if (doInitAttempt > 3)
+      if (doInitAttempt > 30)

[kzar, 2017/12/07 13:28:33]

With other versions of Firefox e.g. 57 I found that sending every 100ms often
triggered the bug where sending seemed successful but with a response of
`undefined`, so I only retried every second in attempt to avoid that. With
Firefox 51 even that wasn't enough so I figured out this other approach. Since
we now have a way of detecting the problem I've switched back to 100ms again to
reduce the "Loading..." delay for the user.

         return;
 
       browser.tabs.sendMessage(popupPageId, {
         type: "composer.dialog.init",
         sender: sender.page.id,
         filters: message.filters
+      }).then(response =>
+      {
+        // Sometimes sendMessage incorrectly reports a success on Firefox, so
+        // we must check the response too.
+        if (typeof response == "undefined")

[Wladimir Palant, 2017/12/12 12:14:52]

Nit: why not `if (!response)`?

[kzar, 2017/12/12 12:33:14]

Done.

+          throw new Error();
       }).catch(e =>
       {
         // Firefox sometimes sets the status for a window to "complete" before
         // it is ready to receive messages[1]. As a workaround we'll try again a
         // few times with a second delay.
         // [1] - https://bugzilla.mozilla.org/show_bug.cgi?id=1418655
-        setTimeout(doInit, 1000);
+        setTimeout(doInit, 100);
       });
     };
     if (window.tabs[0].status != "complete")