bug#62032: 28.2; `switch-frame' event exits incremental search

[Juri Linkov]

>> ;; open second frame
>> C-x 5 b *Messages* RET
>> 
>> ;; switch back to first frame showing scratch buffer
>> C-x 5 o 
>> 
>> ;; go to beginning of scratch buffer
>> ESC <
>> 
>> ;; isearch for "buffer"
>> C-s buffer
>> 
>> <switch to the second Emacs frame by window manager means, for example, 
>> M-Tab>
>> 
>> The last step on my Emacs would exit the incremental search on the first 
>> Emacs frame.
>> 
>> >From this comment in isearch.el:
>> 
>>     ;; Pass frame events transparently so they won't exit the search.
>>     ;; In particular, if we have more than one display open, then a
>>     ;; switch-frame might be generated by someone typing at another keyboard.
>>     (define-key map [switch-frame] nil)
>>     (define-key map [delete-frame] nil)
>>     (define-key map [iconify-frame] nil)
>>     (define-key map [make-frame-visible] nil)
>>     (define-key map [mouse-movement] nil)
>>     (define-key map [language-change] nil)
>> 
>> I would deduce that this should not happen.
>> 
>> When I bind #'ignore to [switch-frame] instead of nil things work as 
>> expected (by me).
>
> Juri, could you please look into this?

This looks related to bug#41338 that is still unfixed.
But maybe 'ignore is really the right way to fix, this needs testing.