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.

From retroj: This is not an isearch bug in particular but a general bug that
affects all minibuffer interactions. I think that the solution to this is to
hook onto navigation [and buffer navigatoin] events, so that any ongoing
interactive command be cancelled when the buffer is navigated to a different page.

Here is a thought. Currently, the main reason this bug crops up is because
people use the mouse to follow links, and mouse events are not integrated with
conkeror's keyboard event handling. If we integrated mouse events tightly into
the system that handles keyboard events, this bug would disappear, because if
you clicked the mouse during an ongoing interaction, conkeror would cancel the
interaction and issue a message like: "Key sequence not bound: C-x click-1"