Cant change formatting of selected text

Summary:

In the latest dev it's impossible to change text formatting (color, font, size, ...) for the selected region of text.

Bisecting points towards inkscape@3f633c9d

Changing style for whole text object is still possible.

Steps to reproduce:

1. open inkscape
2. create text and type something
3. select part of text
4. try changing color or other style property -> nothing

What happened?

Selected text region doesn't change.

What should have happened?

Style for selected region should have changed.

Sample attachments:

Version info

Inkscape 1.5-dev (ae6cffc760, 2025-07-12, custom)

                      Compile  (Run)
    GLib version:     2.84.3
    GTK version:      4.18.6 (4.18.6)
    glibmm version:   2.84.0
    gtkmm version:    4.18.0
    libxml2 version:  2.14.4
    libxslt version:  1.1.43
    Cairo version:    1.18.4 (1.18.4)
    Pango version:    1.56.4 (1.56.4)
    HarfBuzz version: 11.2.1 (11.2.1)

    OS version:       Arch Linux