White screen of tabs, preview of tabs shows content

[hempeter]

I have noticed occasionally that when restoring Firefox from background I get a white screen instead of the tab I'm trying to view. When I go to switch tabs, I can see the page content in the preview.
Tonight it finally happened while I was near the PC so I got to have a look at the log. The page being restored was a youtube desktop page, so I can get the video with Flash Mass Downloader
https://www.youtube.com/watch?v=CS9DsBd ... pp=desktop

The log from the console:

Code: Select all

TypeError: this.selectedTab is null browser.js:146:246
window.controllers is deprecated. Do not use it for UA detection. browser.js:274:0
This site makes use of a SHA-1 Certificate; it's recommended you use certificates with signature algorithms that use hash functions stronger than SHA-1.[Learn More] watch
JavaScript 1.7's let expressions are deprecated ScriptSurrogate.jsm:208:43
NativeWindow.pageactions is deprecated. Please use resource://gre/modules/PageActions.jsm instead browser.js:235:0
ReferenceError: Thread is not defined NSA.jsm:147:6

NSA.jsm

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143: _handleClickToPlay: function(obj) {
144:    if (obj instanceof Ci.nsIObjectLoadingContent && ("playPlugin" in obj) && ("activated" in obj) &&
145:        !obj.activated && !Var.get(obj, "activated")) {
146:      Var.set(obj, "activated", true);
147:      Thread.asap(function() obj.playPlugin());
148:    }
149:  },

Being called from elsewhere in NSA:

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327:    } finally {
328:      LoadChecker.remove(wrappedLocation);
329:      
330:      if (accepting) {
331:        if (contentType === CP_TYPE_OBJECT) {
332:          this._handleClickToPlay(ctx);
333:        }

It looks like NSA.jsm isn't including Thread.jsm. So suggesting just adding this line to NSA.jsm:

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Cu.import("resource://noscript_@VERSION@/modules/Thread.jsm");

Has anyone else experienced this before? Potentially it's just my corner case.