I want to mark the following three questions as duplicates, but I can't decide which one should be the 'root'. All of them are related to the usage of the Esc key in a Custom Shortcut within Unity.
Custom shortcut for System Monitor not working - this one I've answered in a while ago and the suggested solution match to a part of the second question (that still unanswered).
Ubuntu 16.04 escape key doesn't work in custom keyboard shortcut - this contains the solution that I suggested, but there is not answer of the main question - why Custom Shortcuts that use Esc key don't work?
Keyboard shortcut Shift + Ctrl + Escape does not work - this one I found after my answer was accepted. There within the comments is provided the true answer - it is a bug, that is reported on Launchpad with number #1350527 and still not resolved. I've added this information into my answer.
Which of these questions I should choose as the 'root' for the duplication?