If I choose the tab "C:\Program Files\VstPlugins\Arturia" and push the find button (inside find panel) I would like to have the search result at the bottom of the chosen tab.
And eachtime I make a search, I want a new search result tab. Not only one.
Show Results In: Source (New Tab) should give you the closest thing to that.
You'll also need to change the name of the Results Collection if you don't want to overwrite previous results with new ones. (Or turn off Clear previous results to add the new results to the end of the old ones, but you probably don't want that.)
Make sure you use Delete REMOVECOLLECTION for that. Otherwise you will delete the original files. If you use the standard configuration, there should be a command for that, under the delete menu item.
You can't delete them from the menu. But if you go up a level from a collection (or use one of the other methods to go to Collections aka coll://) then you can select and delete collections from there.
Deleting a collection won't delete its files. Just make sure it is the collection itself you have selected, not a file or folder inside a collection