Background search requests while editing search filter

[henning-gerhardt]

Describe the bug
While editing / changing the current used filter a lot of search requests are started in the background and may display results which are not wanted or need.

1. First background search is started when the editing of the current used filter is started. If this search is done you can start editing the used filter.

2. Even while you type the new filter or change the filter searches are started and results are displayed or even an error message that the generated query results in a search error.

3. If you are finish the editing nothing is happening if you end the edit with pressing the enter or tab key. You must lost the focus of the filter search that the new filter search is started and the results are displayed.

Expected behavior
Changing the used filter should start a search if you finish the edit of the filter. Finishing should be may enter key and / or tab key or when the filter input field lost its focus.

Release
3.7.1, 3.8.0-RC1, master branch