src/vs/platform/undoRedo/common/undoRedoService.ts/ResourceEditStack/setElementsIsValid
class ResourceEditStack:	public setElementsIsValid(isValid: boolean): void {
		for (const element of this._past) {
			if (element.type === UndoRedoElementType.Workspace) {
				element.setValid(this.resourceLabel, this.strResource, isValid);
			} else {
				element.setValid(isValid);
			}
		}
		for (const element of this._future) {
			if (element.type === UndoRedoElementType.Workspace) {
				element.setValid(this.resourceLabel, this.strResource, isValid);
			} else {
				element.setValid(isValid);
			}
		}
	}