Decorations are improper on undo

Reproducible in vscode.dev or in VS Code Desktop?

• Not reproducible in vscode.dev or VS Code Desktop

Reproducible in the monaco editor playground?

• Not reproducible in the monaco editor playground

Monaco Editor Playground Link

https://microsoft.github.io/monaco-editor/playground.html?source=v0.50.0#XQAAAAJOAwAAAAAAAABBqQkHQ5NjdMjwa-jY7SIQ9S7DNlzs5W-mwj0fe1ZCDRFc9ws9XQE0SJE1jc2VKxhaLFIw9vEWSxW3yscw2TFFKXzoBtNlUc7JzEx8NDAUbFLl_jqQ-13Gd-1RJYH2Zt9Ji-HKLTQUAY3dr9vTn3QH3Ox7hyIstkn4D6ZgA6N_RtXb_HexBA6A5D_L5VxZvx6s0f-RwMssATjNUJpb9kRqAa052ldBleV6_U8X6JnEBsGPqfGqZ87bKknyqjy3E23r3KPMjf81SjBsa5BcM7-d4u3fo-eUpOtuI5uC9JI029j_XR8UAKeRFfKhnU0_yB4TuUHTO433mmfZMWSozpRO45JzMlhV12g44qux8ZlGx-pM-IMoNWmYjf4bwsDbeuePq5Bjwc44ixyPWydGF3zPUbs-gPwLCwwjj9t4qLtmqptgM1Ydt6Wse7qZDIMhd9VX7HKQWKAOVOyu9ZN26-HTHTQ1oKuLC3a1vsdpv1Ia0oafZdS6teRsd9LfelyHfjzq9KU0Q9KVXGy4NamprsOMUOMJTHN9hKYwRR8IblIVSX7C5H4TJ9pTfdtCuHnc9yCMZ22U3GAu3-DpUveWkpQ8iMmNJtPJIQCEG_rZTcDABslJzhSs-0yPpfdCgAD5MjmHn1SfP6WxLkZkCaQ7DSlkMAxX0GMdDvoZBVUzyW6308oAFPZmwbNr_1Ek_1mRdXvG0xKiahF2xN5qVP_2sJXM

Monaco Editor Playground Code

var jsCode = "function Person(age) {if (age)123456{this.age = age;}}"

var editor = monaco.editor.create(document.getElementById("container"), {
	trimAutoWhitespace: false,
	value: jsCode,
	language: "javascript",
});

setTimeout(() => {
	editor.executeEdits("", [{
		range: new monaco.Range(1, 1, 1, 99),
		text: "function Person(age) {\n  if (age)123456{\n    this.age = age;\n  }\n}",
		forceMoveMarkers: true,
	}]);
	editor.createDecorationsCollection([
		{
			range: new monaco.Range(2, 7, 2, 10),
			options: { inlineClassName: "myInlineDecoration", shouldFillLineOnLineBreak: false },

		},
	]);
	console.log(editor)
}, 3000)

Reproduction Steps

3 seconds after the editor was loaded, I added a decorator ("age"), and then I withdrew (ctrl+z), and the original "age" in the editor changed to "123".

1. open url
2. wait a few seconds
3. undo when editor content changes

Actual (Problematic) Behavior

The content of the decorator has changed

Expected Behavior

after the retraction, the decorator content is normal.

Additional Context

No response

Use the linked Monaco Editor Playground and its executeEdits/createDecorationsCollection setup as the entry point; reproduce the Ctrl+Z case where the decoration covering “age” displays “123”. Trace how undo updates decoration ranges and content, and consider the issue complete when the decoration still covers the intended text after undo.