Filtering and code completion do not work when '#' character is used

I've reproduced the problem in lsp-sample (description of my original post moved below).

The code completion does not work with # character. How to make it work?

Added CompletionItem for #1000:

connection.onCompletion(    (_textDocumentPosition: TextDocumentPositionParams): CompletionItem[] => {        return [            {                label: 'TypeScript',                kind: CompletionItemKind.Text,                data: 1,            },            {                label: 'JavaScript',                kind: CompletionItemKind.Text,                data: 2,            },            {                label: '#1000',                kind: CompletionItemKind.Text,                data: 3,            },        ];    });

Now typing # or #1 does not show/filter the completion list. Choosing #1000 from the list does not completes properly, i.e. makes ##1000.

For filtering tried adding filterText: '#[0-9]+', or filterText: '#', to no avail.

For completion tried below but it does not work when there is something before #1 in the same line:

textEdit: InsertReplaceEdit.create('#1000',                    Range.create(                        Position.create(_textDocumentPosition.position.line, 0),                        _textDocumentPosition.position                    ),                    Range.create(                        Position.create(_textDocumentPosition.position.line, 0),                        _textDocumentPosition.position                    )                ),

=================(My previous post)=======================

I have the following code completion list defined:

[    {"jsonrpc": "2.0","id": 6,"result": [            {"label": "G253","kind": 15,"insertTextFormat": 2,"data": 106            },            {"label": "G254","kind": 15,"insertTextFormat": 2,"data": 107            },            {"label": "G255","kind": 15,"insertTextFormat": 2,"data": 108            },            {"label": "#3000","kind": 15,"insertTextFormat": 2,"data": 215            },            {"label": "#3001","kind": 15,"insertTextFormat": 2,"data": 216            },            {"label": "#3002","kind": 15,"insertTextFormat": 2,"data": 217            },            {"label": "#3003","kind": 15,"insertTextFormat": 2,"data": 218            },            {"label": "#3004","kind": 15,"insertTextFormat": 2,"data": 219            }        ]    }]

When typing # and triggering code completion, further typing #3 does not make the list filtered. Then selecting for example #3002 from the list inserts double hash: ##3002.What am I missing here?

However there is no problem if I use other character than #, for example G. Then everything works with no problem - proper completion list filtering and inserting, for example G254.