TYPO3 Core

Once livesearch can't find results for a search string, following searches are not executed.
This is the default behaviour of jQuery autocomplete. The option
preventBadQueries: false
can be used to fix the issue.

Example 1:
An editor wants to find tt_content with UID 12345 entering '#content:12345'.
The record exists and is accessible.

The search fires once '#co' is entered but does not find anything. Subsequent characters are not send to the Server.

Entering '#content:12345' via copy&paste as a complete string works.

Example 2:
An admin wants to find the same record by searching for the UID only.

Entering '123' might find some record containing the string '123' in bodytext.
Entering '1234' finds nothing.
Entering '12345' does not execute the search.
Copy&pasting the whole string works.