Update: Bug report 4217 has been opened regarding this issue.
I cannot get the X11 / Gnome Clipboard to paste into vim/gVim 8.0.1453 under Ubuntu 18.04 with Gnome 3.26 installed when using the Gnome Clipboard indicator. I always get the message:
E353: Nothing in register "+
Yet, I tried the following settings:
:set clipboard=unnamed :set clipboard=unnamedplus :set clipboard=unnamed,unnamedplus :set clipboard=unnamed,unnamedplus,autoselect,exclude:cons\|linux
Copy and paste with any other application through the system clipboard after choosing an item in the Gnome Clipboard indicator works well. The problem lay only with gVim/vim.
However, if say I copy (CTRL-C) from LibreOffice to gVim, it works fine. Any clue what is going on or how to trace the problem? This inconsistency is baffling.