[Lazarus] Opening file in editor window if it's loaded in another editor window

[Jürgen Hestermann]

I have 2 editor windows ("Source Editor" and ""Source Editor (2)"
and have loaded "Unit1.pas" in both of these windows.
After I have now (inadvertently) closed "Unit1.pas" in "Source Editor"
I cannot load it again with "File Open".
It just happens nothing.

A known bug?