Matt Wobensmith [:mwobensmith][:matt:] Reporter
	Description • 9 years ago

1. Install and launch Fx42.0a2 on Mac with a *clean profile*.
2. Open two private windows.
3. Dock one of the windows to the other.

Result:
Docked window does not render, displays spinner.

Expected:
Render please.

	Matt Wobensmith [:mwobensmith][:matt:] Reporter
	Comment 1 • 9 years ago

Seems to affect Aurora Fx42.0a2, 2015-08-12, but not today's Nightly. 

Haven't tried Win/Linux yet.

	Brian Grinstead [:bgrins]
	Comment 2 • 9 years ago

(In reply to Matt Wobensmith from comment #0)
> Created attachment 8647819 [details]
> Screen Shot 2015-08-13 at 5.41.30 PM.png
> 
> 1. Install and launch Fx42.0a2 on Mac with a *clean profile*.
> 2. Open two private windows.
> 3. Dock one of the windows to the other.

I can confirm this is a problem.  Interestingly when I defocused the window for a while and came back to it at some point it was rendered.  It must be related to e10s.

Here's the error I see in the Browser Console: 'SecurityError: The operation is insecure. tabbrowser.xml:5042:0'.  This points to: setEffectAllowedForDataTransfer, the line 'var sourceNode = dt.mozGetDataAt(TAB_DROP_TYPE, 0)'

	Brian Grinstead [:bgrins]
	Comment 3 • 9 years ago

(In reply to Matt Wobensmith from comment #1)
> Seems to affect Aurora Fx42.0a2, 2015-08-12, but not today's Nightly. 

Can you please confirm that you aren't seeing it in Nightly with e10s enabled?

	Brian Grinstead [:bgrins]
	Comment 4 • 9 years ago

Looks like this js hasn't changed in a long time, must have been a platform change that fixed this in Nightly.  It'd be great to know if this is a regression or if it's a problem in 40/41 with e10s enabled as well.

	Brian Grinstead [:bgrins]
	Comment 5 • 9 years ago

Actually, I think this doesn't have anything to do with being in private browsing mode.  I suspect it has to do with moving an about: page that's running in e10s into another window (in this case, about:privatebrowsing)

Alertnative STR:

Open a normal window
Open a second normal window, and navigate to about:privatebrowsing inside it (which is loaded in e10s)
Drag the tab from the second window into the first one

Expected:

The page renders

Actual:

Neverending spinner

	Matt Wobensmith [:mwobensmith][:matt:] Reporter
	Comment 6 • 9 years ago

(In reply to Brian Grinstead [:bgrins] from comment #3)
> (In reply to Matt Wobensmith from comment #1)
> > Seems to affect Aurora Fx42.0a2, 2015-08-12, but not today's Nightly. 
> 
> Can you please confirm that you aren't seeing it in Nightly with e10s
> enabled?

Does not appear to happen in Nightly with e10s enabled.

	Matt Wobensmith [:mwobensmith][:matt:] Reporter
	Comment 7 • 9 years ago

(In reply to Brian Grinstead [:bgrins] from comment #4)
> Looks like this js hasn't changed in a long time, must have been a platform
> change that fixed this in Nightly.  It'd be great to know if this is a
> regression or if it's a problem in 40/41 with e10s enabled as well.

How does one turn on e10s in 40/41, since the UI is not present in Preferences?

	Brian Grinstead [:bgrins]
	Comment 8 • 9 years ago

(In reply to Matt Wobensmith from comment #7)
> (In reply to Brian Grinstead [:bgrins] from comment #4)
> > Looks like this js hasn't changed in a long time, must have been a platform
> > change that fixed this in Nightly.  It'd be great to know if this is a
> > regression or if it's a problem in 40/41 with e10s enabled as well.
> 
> How does one turn on e10s in 40/41, since the UI is not present in
> Preferences?

Ah, apparently there isn't a way to do that.. I tried using mozregression to figure out when this got fixed, but I can't seem to ever reproduce it in a local build (even from before the aurora merge date).  So that makes me wonder if there is some setting enabled in nightly that's fixing the problem.

	Tracy Walker [:tracy]
	Comment 9 • 9 years ago

I can reproduce on latest DevEd but not on latest Nightly. Which confirms previous reports/ 

However, it is expected that you cannot drag a private browsing window into a regular browsing window. The bug as reported is dragging from a private browsing tab from its window to another private browsing window.

Interestingly, if you drag the endless spinning tab back out, to create a new PB window, the tab then loads fine.

	Mike Conley (:mconley) (:⚙️)
	Comment 10 • 9 years ago

Hey Blake - can I take this off your hands?

	Blake Kaplan (:mrbkap) (inactive) Assignee
	Comment 11 • 9 years ago

Marking this WFM based on previous comments.