Some fill and stroke edits on subselection extend to entire text line

Migrated from: https://bugs.launchpad.net/inkscape/+bug/1273503

Steps to reproduce:

• open Inkscape
• enter: ABCDEFG
• select all letters
• turn on stroke, 1 px wide
• select only CDE
• using the fill and stroke dialog, change the stroke to 3 px wide

What happened?

The stroke width of the entire line changes.

What should have happened?

A new tspan with the new stroke size is created, so only the selected text changes its stroke width.

Also affects

• changing from a solid fill to a pattern.
• changing from a solid fill to a gradient

Not affected:

• changing from one fill/stroke color to another fill/stroke color

Inkscape Version and Operating System:

• Inkscape Version: 1.1-dev (12e2a09, 2020-02-19)
• Operating System: Windows 10
• Operating System version: 10.0.18362

Migration info

• Confirmed on Windows XP, Inkscape 0.48.4 and trunk revision 12982.

Workaround:

select the element directly in the XML editor and apply the style changes.