type search term such as 'string' and press enter. This must be a string that occurs in different chats.
click on one of the results. We will assume that we clicked a result for the Gajim MUC. After you click on the Gajim MUC result, this causes the 'Search all Chats' option to be automatically unselected and display the selected message.
scroll down in the search results list until the search results list loads/generates more results. The newly generated/loaded results matching from any chats will now show as existing in the Gajim MUC even when they do not.
click on a search result that you know does not actually belong to the Gajim MUC. This will cause gajim to scroll up in the Gajim MUC, seemingly endlessly, and become unresponsive.