Calc document gets into 'read only' from itself

One my calc doc became READ ONLY (withou me doing it!!!)
Please, i tried to “unlock” it

  1. tools- options-security
  2. file-properties

But I can’t see the option to make the file so that I can make changes in there again!
Please, if someone helped I woudl ne gratefull!
(Noone else did it, maybe just me unwilingly, because it is my personal netbook!)- do not think that I want to make not permitted chaanges in read - onlies, it is my own document!!!

p.s. file-properties- security all the options are grey(inactivated), I can only click OK. Then I DID IT but nothing changed.
Well, my netbook IS very unstalbe, but I would be grateefull if someone hleped me here!

You can try clicking on Edit File icon from toolbar.

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You can also use File | “Save as” and save the document with another name.
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