Tests that changing a property is undone properly.

Initial value
[expanded] 
element.style { ()

[expanded] 
.container { (<style>)
    font-weight: bold;

[expanded] 
div { (user agent stylesheet)
    display: block;
    unicode-bidi: isolate;

After changing property
[expanded] 
element.style { ()

[expanded] 
.container { (<style>)
    font-weight: normal;

[expanded] 
div { (user agent stylesheet)
    display: block;
    unicode-bidi: isolate;

After undo
[expanded] 
element.style { ()

[expanded] 
.container { (<style>)
    font-weight: bold;

[expanded] 
div { (user agent stylesheet)
    display: block;
    unicode-bidi: isolate;

After redo
[expanded] 
element.style { ()

[expanded] 
.container { (<style>)
    font-weight: normal;

[expanded] 
div { (user agent stylesheet)
    display: block;
    unicode-bidi: isolate;