Do you mean the bug is now invalid? It sounds like your screen is set to very dim and by "almost black" you mean Ubuntu-grey. Yes, it should change colour that way with proximity. This is a design decision inherited from upstream Gnome 3.26 and not something that Ubuntu chose.
** Changed in: gnome-shell-extension-ubuntu-dock (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1719119 Title: Dock opacity changes when running certain applications. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell-extension-ubuntu-dock/+bug/1719119/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs