Minor revisions to Android key bindings

* etc/PROBLEMS (Runtime problems specific to Android): Document
inappropriate generation of F3 on certain systems.

* lisp/bindings.el ([iconify-frame], [make-frame-visible]):
Update references to long-obsolete ignore-event command.

* lisp/term/android-win.el ([KEYCODE_NOTIFICATION], [\83]):
Ignore these two nuisance keys by default.

etc/PROBLEMS

@@ -3666,7 +3666,7 @@ result that the next redisplay recenters the window around this outdated
 position.  There is no solution but installing a more
 cooperative--and preferably free--input method.
 
-** The default input method sometimes performs edits out of place in large buffers.
+** The default input method performs edits elsewhere than point in large buffers.
 
 When first reactivated in a window after having been dismissed, certain
 heuristics applied by the "Android Keyboard (AOSP)" input method to
@@ -3680,6 +3680,14 @@ in the input method that can be easily reproduced by inserting lengthy
 documents into any text editor, with no real solution except avoiding
 edit suggestions from recently-reactivated input methods.
 
+** The F3 key appears to be spontaneously activated.
+
+It is possible that this is a product of your inadvertently contacting
+the back-facing fingerprint sensor, which generates F3 key events on
+devices manufactured by OnePlus and possibly others.  Sadly, to the best
+of our knowledge such events cannot be distinguished from legitimate
+keypresses.
+
 * Build-time problems
 
 ** Configuration

lisp/bindings.el

@@ -978,9 +978,8 @@ language you are using."
 ;;        It seems that they can't because they're handled via
 ;;        special-event-map which is used at very low-level.  -stef
 (global-set-key [delete-frame] 'handle-delete-frame)
-(global-set-key [iconify-frame] 'ignore-event)
-(global-set-key [make-frame-visible] 'ignore-event)
-
+(global-set-key [iconify-frame] 'ignore)
+(global-set-key [make-frame-visible] 'ignore)
 
 ;These commands are defined in editfns.c
 ;but they are not assigned to keys there.

lisp/term/android-win.el

@@ -617,6 +617,16 @@ accessible to other programs."
   :ccl-decoder 'android-decode-jni
   :ccl-encoder 'android-encode-jni)
 
+
+;; Default key definitions.
+
+;; Suppress KEYCODE_NOTIFICATION, which has been observed to be
+;; spontaneously generated on certain tablets, so that the user may not
+;; be disturbed by intrusive messages when it is registered.
+(global-set-key [KEYCODE_NOTIFICATION] #'ignore)
+(global-set-key [\83] #'ignore) ; KEYCODE_NOTIFICATION on pre-Honeycomb
+                                ; releases.
+
 
 (provide 'android-win)
 ;; android-win.el ends here.