Cannot use altwin:ctrl_alt_win keyboard option with "English (international AltGr dead keys)" keyboard layout

[Erik Hetzner]

Platform: Ubuntu 15.10 (wily) + gnome3 team ppa

Steps to reproduce:

1. Enable "altwin:ctrl_alt_win" keyboard option using gnome-tweak-tool (see ctrl_alt_win.png, attached)
2. Use "English (international AltGr dead keys)" keyboard layout (see input_sources.png)

Expected behavior:

- Right super key on keyboard will be mapped to "ISO_Level3_Shift" key

Actual behavior:

- Right super key on keyboard is mapped to Alt_R key.

See attached screenshots for the difference between the layouts. I would expect the keys to be the same, but in a different order. This behavior prevents me from using this keyboard option with the "AltGr" dead key, because it is not available on the keyboard if the the altwin:ctrl_alt_win option is used.