Why not leave the line numbers as they were before filtering and simply not display the filtered lines? It would look something like: 
1211 dfgsdfsdfg
1212 sdfgdfgsdf
1213 sdfgsdfgsdfg
1273 sdfgsdfgsdfg
1274 sdhgsfdg

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The only problem with this approach is when the filter would filter out most (or all) of the lines in the buffer. The display would be rather empty then.

In reply to Re: Further on buffering huge text files by Jaap
in thread Further on buffering huge text files by spurperl

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