Björn Bidar <bjorn.bidar@thaodan.de> writes:

>>> * Preconditions
>>> - gnus-other-frame-object is a dead frame
>>
>> May you please describe when `gnus-other-frame-object' could become a
>> dead frame?
>
> I assume when  the frame that is in the object was closed.
>
> E.g. for example to trigger this state again I closed the Gnus frame I
> was writing this reply in.  Afterwards the frame is dead.

Then, why not simply the attached patch?