diff --git a/src/LiveCards.jl b/src/LiveCards.jl
index d8ebc3d..12a4bf5 100644
--- a/src/LiveCards.jl
+++ b/src/LiveCards.jl
@@ -1025,20 +1025,25 @@ _selection_objects(s::_ShapeChange) = isnothing(s.old) ? Any[s.new] : Any[s.new,
     _shape_changed!(gui, obj, old, new)
 
 An input on the card of `obj` changed the code of its constructor from `old` to `new`: the code of
-its `origin` becomes `new` (the autosave writes it to the line of `obj`, see `_project_parts`), the
-handles of `obj` in the pool draw it again (`BeamletOptics.rerender!`), and the change is recorded
-in the undo history, see `_ShapeChange`.
+its `origin` becomes `new` in the `gui` and in every window linked with it that shows `obj` (see
+`open_system`), such that the window of the project saves it (the autosave writes it to the line of
+`obj`, see `_project_parts`); the handles of `obj` in the pools of these windows draw it again
+(`BeamletOptics.rerender!`), and the change is recorded in the undo history of the `gui`, see
+`_ShapeChange`.
 """
 function _shape_changed!(gui::LiveView, @nospecialize(obj), old::String, new::String)
-    comp = gui.components
     # e.g. removed by the input
-    haskey(comp.origin, obj) || return nothing
-    comp.origin[obj] = merge(comp.origin[obj], (; code = new))
-    for oh in _pool_handles(gui, obj)
-        Base.invokelatest(BMO.rerender!, oh)
+    haskey(gui.components.origin, obj) || return nothing
+    for v in unique(objectid, Any[gui, gui.links.views...])
+        origin = v.components.origin
+        haskey(origin, obj) || continue
+        origin[obj] = merge(origin[obj], (; code = new))
+        for oh in _pool_handles(v, obj)
+            Base.invokelatest(BMO.rerender!, oh)
+        end
+        _update_selection_box!(v.controls)
     end
-    _update_selection_box!(gui.controls)
-    comp.recording && _record_shape!(gui, obj, old)
+    gui.components.recording && _record_shape!(gui, obj, old)
     return nothing
 end
 
diff --git a/src/LiveLinks.jl b/src/LiveLinks.jl
index 91211da..7fecd16 100644
--- a/src/LiveLinks.jl
+++ b/src/LiveLinks.jl
@@ -219,6 +219,11 @@ function _link!(gui::LiveView, new::LiveView, system)
         to.system[obj] = system
         to.origin[obj] = get(from.origin, obj, nothing)
     end
+    # the code of the objects and sources that the view started with as well, e.g. of a project:
+    # a change of their shape in `new` reaches the code of every view, see `_shape_changed!`
+    for obj in Iterators.flatten((system.objects, _sources_of(gui, system)))
+        haskey(from.origin, obj) && !haskey(to.origin, obj) && (to.origin[obj] = from.origin[obj])
+    end
     for obj in from.removed
         if haskey(from.source_systems, obj)
             _has(from.source_systems[obj], system) || continue
diff --git a/test/TestLiveProjectOwnTypes.jl b/test/TestLiveProjectOwnTypes.jl
index f739719..010e077 100644
--- a/test/TestLiveProjectOwnTypes.jl
+++ b/test/TestLiveProjectOwnTypes.jl
@@ -129,6 +129,32 @@ end
         close(gui)
     end
 
+    @testset "a change of the shape in a second window is saved (#88)" begin
+        dir = project()
+        gui = open_project(dir; display = false, const_kw...)
+        k1 = obj(gui, :K1)
+        second = open_system(gui, only(GUI._systems(gui)); display = false)
+        select!(second, k1)
+        Makie.set_close_to!(card_widget(second, k1, :width), 40.0)
+        @test k1.shape.diameter ≈ 0.04
+        # the code in both windows, saved by the window of the project
+        @test second.components.origin[k1].code == "Block(0.04, 0.005)"
+        @test gui.components.origin[k1].code == "Block(0.04, 0.005)"
+        @test GUI._autosave!(gui; force = true) === :saved
+        @test startswith(line(dir, :K1), "@component K1 = Block(0.04, 0.005)")
+        # undo in the second window: the old shape again, also in the files
+        @test GUI._undo!(second.controls)
+        old = obj(gui, :K1)
+        @test old !== k1 && old.shape.diameter == 0.025
+        @test GUI._autosave!(gui; force = true) === :saved
+        @test startswith(line(dir, :K1), "@component K1 = Block(0.025, 0.005)")
+        @test GUI._redo!(second.controls)
+        @test GUI._autosave!(gui; force = true) === :saved
+        @test startswith(line(dir, :K1), "@component K1 = Block(0.04, 0.005)")
+        close(second)
+        close(gui)
+    end
+
     @testset "a type without constructor_code" begin
         dir = project()
         gui = open_project(dir; display = false, const_kw...)