CSS style is ignored when copying objects with a class into another document if grouped
#### Steps to reproduce:
- open Inkscape
- open file visio_exported_svg.svg (attached)
- hit ctrl-C for copying a box with text(see image1)
- open a new file
- hit ctrl-V for pasting
#### What happened?
- in the new file, the box with text become black-filled (see attached image2)
#### What should have happened?
- the box with text should not be black-filled
#### Inkscape Version and Operating System:
- Inkscape Version: Inkscape 1.1-dev (efef7d6, 2020-02-20)
- Operating System: Windows 10 home version 1903

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With respect to the above problem, @nathanal has the following comments (edited by @nathanal :wink:)
The css info inside the style tags aren't copied over or applied to the objects (though the objects retain their class/id). Condition: the objects that have a class are inside a group. [Minimal test case](https://gitlab.com/inkscape/inbox/uploads/8e72e2a256c25ecb8b0532d5bcd7db54/drawing.svg)
Copying the group over to a new document leaves the rect with class="pinky" but the style info isn't copied over so fill is left unset.
If you ungroup before copying over, the fill (and for some reason stroke-width, which wasn't set) is applied directly to the rectangle.
issue