This bug appears when using the tab-bar and/or clicks-in-new-buffer modes.

1. Load a page.
2. isearch for something.
3. Middle click to load a new page and switch to that page by clicking its tab
or click the X on the tab to close the buffer. In either case, do not close the
isearch.
4. Continue isearching in box from previous page.
5. Observe failure which of course varies depending on whether you opened a new
buffer or closed the old buffer. In the latter case it is sometimes difficult
get the isearch to close at all.