[Android Apps and Games] zanfix:
Ok so:

Arrow keys issue is gone, works fine.

For the mouse issue I got the following results:

Samsung galaxy S9+

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SAMSUNG DEX
-------------------

LMB down

04-26 19:46:38.856 13073 13073 I Sparkle : MotionEvent1 source=12290 action=0
04-26 19:46:38.856 13073 13073 I Sparkle : MotionEvent2 source=12290 action=11

LMB up

04-26 19:46:56.917 13073 13073 I Sparkle : MotionEvent2 source=12290 action=12
04-26 19:46:56.918 13073 13073 I Sparkle : MotionEvent1 source=12290 action=1

RMB down

04-26 19:47:27.026 13073 13073 I Sparkle : MotionEvent1 source=12290 action=0
04-26 19:47:27.026 13073 13073 I Sparkle : MotionEvent2 source=12290 action=11

RMB up

04-26 19:47:52.273 13073 13073 I Sparkle : MotionEvent2 source=12290 action=12
04-26 19:47:52.274 13073 13073 I Sparkle : MotionEvent1 source=12290 action=1

Mousewheel up

04-26 19:48:54.685 13073 13073 I Sparkle : MotionEvent2 source=12290 action=7
04-26 19:48:54.686 13073 13073 I Sparkle : MotionEvent2 source=12290 action=8

Mousewheel down

04-26 19:49:42.501 13073 13073 I Sparkle : MotionEvent2 source=12290 action=7
04-26 19:49:42.502 13073 13073 I Sparkle : MotionEvent2 source=12290 action=8

----------------------------------
PLAIN SCREEN MIRRORING
----------------------------------

LMB down

04-26 19:55:41.078 19072 19072 I Sparkle : MotionEvent2 source=8194 action=10
04-26 19:55:41.083 19072 19072 I Sparkle : MotionEvent1 source=8194 action=0
04-26 19:55:41.090 19072 19072 I Sparkle : MotionEvent2 source=8194 action=11

LMB up

04-26 19:57:25.707 19072 19072 I Sparkle : MotionEvent2 source=8194 action=12
04-26 19:57:25.709 19072 19072 I Sparkle : MotionEvent1 source=8194 action=1
04-26 19:57:25.710 19072 19072 I Sparkle : MotionEvent2 source=8194 action=9
04-26 19:57:25.728 19072 19072 I Sparkle : MotionEvent2 source=8194 action=7

RMB down

04-26 19:59:53.765 19072 19072 I Sparkle : KeyEvent source=8194 keyCode=4
04-26 19:59:53.769 19072 19072 I Sparkle : MotionEvent2 source=8194 action=7

RMB up

04-26 19:59:54.253 19072 19072 I Sparkle : MotionEvent2 source=8194 action=9
04-26 19:59:54.261 19072 19072 I Sparkle : MotionEvent2 source=8194 action=7

Mouse wheel up

04-26 20:02:56.587 19072 19072 I Sparkle : MotionEvent2 source=8194 action=7
04-26 20:02:56.589 19072 19072 I Sparkle : MotionEvent2 source=8194 action=8

Mouse wheel down

04-26 20:03:15.959 19072 19072 I Sparkle : MotionEvent2 source=8194 action=7
04-26 20:03:15.960 19072 19072 I Sparkle : MotionEvent2 source=8194 action=8

Google pixelc

LMB down

04-26 19:01:23.671 26329 26329 I Sparkle : MotionEvent2 source=8194 action=10
04-26 19:01:23.672 26329 26329 I Sparkle : MotionEvent1 source=8194 action=0
04-26 19:01:23.672 26329 26329 I Sparkle : MotionEvent2 source=8194 action=11

LMB up

04-26 19:01:48.993 26329 26329 I Sparkle : MotionEvent2 source=8194 action=12
04-26 19:01:49.010 26329 26329 I Sparkle : MotionEvent1 source=8194 action=1
04-26 19:01:49.011 26329 26329 I Sparkle : MotionEvent2 source=8194 action=9
04-26 19:01:49.028 26329 26329 I Sparkle : MotionEvent2 source=8194 action=7

RMB down

04-26 19:02:35.733 26329 26329 I Sparkle : MotionEvent2 source=8194 action=10
04-26 19:02:35.734 26329 26329 I Sparkle : MotionEvent1 source=8194 action=0
04-26 19:02:35.751 26329 26329 I Sparkle : MotionEvent2 source=8194 action=11

RMB up

04-26 19:03:26.530 26329 26329 I Sparkle : MotionEvent2 source=8194 action=12
04-26 19:03:26.531 26329 26329 I Sparkle : MotionEvent1 source=8194 action=1
04-26 19:03:26.531 26329 26329 I Sparkle : MotionEvent2 source=8194 action=9
04-26 19:03:26.545 26329 26329 I Sparkle : MotionEvent2 source=8194 action=7

Mousewheel up

04-26 19:04:17.047 26329 26329 I Sparkle : MotionEvent2 source=8194 action=7
04-26 19:04:17.047 26329 26329 I Sparkle : MotionEvent2 source=8194 action=8

Mousewheel down

04-26 19:04:53.039 26329 26329 I Sparkle : MotionEvent2 source=8194 action=7
04-26 19:04:53.040 26329 26329 I Sparkle : MotionEvent2 source=8194 action=8