OS: Windows 10 - 64bit
When performing a search for files twice nothing is found.
Effect: Irritating functionality.
To reproduce:
1. In XnView browser select a folder with subfolders and images in it.
2. Select "Tools > Search"
3. Enter a search patterns which will return some results.
4. Select "View..."
5. Select "Tools > Search" to start a second search.
6. Enter a search pattersn which should return other results
Actual behaviour (bug): No results are found. (Reason is that the existing search results is searched.)

Expected behaviour: The selected folder should be searched, again.
Note: From my point of view the main use case is that a search is performed on a folder and subsequent searches are also performed on a folder. It might be an interesting extra use case to search the search results, but this is not supposed to be the standard use case. For searching the search results an entry "<search results>" might be added to the drop down list.