Question about minibuffer and child frames (Posframe)

[Gerd Möllmann]

Hi Martin,

I have a question about minibuffer handling with child frames. Actually,
it's something that currently behaves differently on GUI and tty with
Posframe, via Vertico-Posframe, plus consult-buffer and similar. Since
I've looked at this for two hours today without being able to tell what
I'm missing here, I thought I'd just ask if you, or anyone else, has an
idea where to look.

Here's what I see:

On GUI, consult-buffer pops up a child frame, which has, AFAICT, a
minibuffer at the top. The cursor is in that minibuffer. The minibuffer
ih the parent frame looks inactive. There is no prompt or anything else.
That's how it should be.

With my new code on tty, the same child frame pops up, but this time the
child frame's minibuffer contains a prompt and what I type is displayed
there and so on, but it doesn't have a visible cursor. The parent
frame's minibuffer this time contains the prompt and the cursor, too.

Any idea what that could be?