I did not ask about the use of double slashes.
Probably my post was written in a confusing way.
What I am asking is why the following symbol is not displayed correctly:
According to your guide, 4'
is the correct way to display the symbol above. However, Dorico displays it as follows:
In the following example, I have typed the same characters as in your example, but the display is different:
Why does it happen?