1297477 - [e10s] blank tabs being created when moving non-e10s tabs into a e10s window

Status: RESOLVED WONTFIX

(Firefox :: Tabbed Browser, defect)

Description

[Kamil Jozwiak [:kjozwiak]]

Blank container tabs are being created when dragging and dropping a container that was created in a non-e10s window into an e10s window. 

STR: (Video Example: https://youtu.be/iRGM1BaC1Gc)

* launch the latest version of m-c which should load a e10s window/tab
* open a non-e10s window via "File -> New Non-e10s Window"
* within the non-e10s window, open a container via "File -> New Container Tab"
* load https://duckduckgo.com within the container and tear the tap from the non-e10s window
* drag and drop the container window into the e10s window that was originally created when launching m-c

You'll notice that dragging the container window/tab that was created in the non-e10s window will create blank tabs when dropping it into the e10s window.

I'm also seeing the following errors when I have the browser console opened and go through the STR mentioned above:

Browser console:

TypeError: draggedTab._dragData is undefined tabbrowser.xml:6171:13
onxbldragendchrome://browser/content/tabbrowser.xml:6171:13

Terminal while using --debug:

JavaScript error: chrome://browser/content/tabbrowser.xml, line 6171: TypeError: draggedTab._dragData is undefined

Comment 1

[Kamil Jozwiak [:kjozwiak]]

This is affecting regular tabs as well, not specific to containers.

Comment 2

[Bill McCloskey [inactive unless it's an emergency] (:billm)]

I don't think we ever plan to support this. Non-e10s windows are a testing feature that will never ship.