Type: story-wide panel changes follow the story's current thread

After Select All in threaded text, the panels read the frames from the
list saved at Select All. A frame that had left the thread still took
Paragraph, Tabs, Justification and Text Styles changes, a frame added
later did not, and when the first saved frame had left, Character,
OpenType and font changes went to that frame alone.

text_story now reads the frames of the edited frame's thread from the
document. Locked and hidden frames stay in the story.

docs/mcp.md

@@ -5071,6 +5071,8 @@ and Cut take. Typing, Delete and Cut replace the whole story as one undo step (`
 frames whose text goes), and a fill, stroke, `type.step` or Character or Paragraph panel change applies to the text of
 every frame (the Character panel sends `text.setRangeStyle {id, story: true}`, which styles every frame's text in one
 undo step). Remove Line Breaks, Remove Paragraph Breaks and Convert to Text also act on the text of every frame, as
+one undo step. The panels change the frames that are in the edited frame's thread at the time of the change, locked and
+hidden frames included, and not a frame that has left it. A caret move or a click ends the story selection.
 one undo step. A caret move or a click ends the story selection. Switching to the Eyedropper keeps the story selected,
 and switching back to a Type tool restores it. `appearance.copyFrom` and `paint.sampleColor` then apply to the text of
 every frame as one undo step, and `appearance.copyFrom` leaves out a frame that is its `source`. While the story stays