The thumbnail and list views should display the current folder content by default. This would not only be more intuitive for users cause that's what most file browsers do (e.g. osx finder), it would also avoid the problems with large result lists.

For example, we had to disable both list and thumbnail views because, the way they are they don't work with large number of pages/assets. Switching from tree to tree to list/gallery view would be sufficient to freeze your app until you got your 300'000 item result list which you probably didn't want to browse anyway.

So the thumbnail and list view should operate in the current folder context by default and switch to result list mode only if you enter a valid search term.