Hidden text-in-shape objects removed when closing and re-opening document.

Summary:

After saving and closing a document with hidden text-in-shape, re-opening the document has no hidden text objects. The tspans have been removed.

Steps to reproduce:

• open Inkscape
• Create some text-in-shape by dragging a text box, then typing.
• Duplicate the text object
• Hide the duplicate text object.
• Save and close the document.
• Open the document again.
• Unhide the previously hidden text object.

What happened?

The original hidden text object is not visible. It's tspan has been removed from the document.

What should have happened?

All text objects should be retained, hidden and visible.

Mentioned earlier here (after issue was closed): inkscape#3326 (comment 1083007250)

Discussion on the forum here:

https://inkscape.org/forums/beyond/object-info-lost-when-closing-and-reopening-after-object-to-path-from-a-copy-of-the-object/

Version info

Inkscape 1.2.1 (9c6d41e410, 2022-07-14)

    GLib version:     2.72.2
    GTK version:      3.24.34
    glibmm version:   2.66.4
    gtkmm version:    3.24.6
    libxml2 version:  2.9.14
    libxslt version:  1.1.35
    Cairo version:    1.17.6
    Pango version:    1.50.7
    HarfBuzz version: 4.4.1

    OS version:       Windows 8.1

Inkscape 1.2 (1:1.2.1+202207142221+cd75a1ee6d)

    GLib version:     2.64.6
    GTK version:      3.24.20
    glibmm version:   2.64.2
    gtkmm version:    3.24.2
    libxml2 version:  2.9.10
    libxslt version:  1.1.34
    Cairo version:    1.16.0
    Pango version:    1.44.7
    HarfBuzz version: 2.6.4

    OS version:       Linux Mint 20.3