Load a document from a file in the local file system.
This menu operation loads an existing document from the local file system, which must use HTML and Content MathML to represent the text and math portions of the document.
You will be prompted to select the file to be opened.
Make changes to the text and math portions of the current document, and use the Save operation to store the new version back to the file in the file system.
Type Alt Shift F, O to open an existing document.
This operation does not modify any file in the file system.