Remote desktop connection from windows 10, with x11vnc and -unixpw argument, weird key events

[adrianalin]

If you'd like to put out an incentive for fixing this bug, you can do so at https://issuehunt.io/r/LibVNC/x11vnc

Describe the bug
Unexpected key events on x11vnc when using -unixpw argument during the login screen which causes prompt to skip login input.

To Reproduce
Run x11vnc:
UNIXPW_DISABLE_SSL=1 x11vnc -forever -repeat -unixpw -dk
Run xrdp service.
Connect from windows 10 remote desktop connection client to linux x11vnc session.
login input is skipped, only password input is expected cause by unexpected key events as seen bellow:

Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22   32 bpp, depth 24, little endian
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22   true colour: max r 255 g 255 b 255, shift r 16 g 8 b 0
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 no translation needed
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 Enabling full-color cursor updates for client ::1
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 Enabling NewFBSize protocol extension for client ::1
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 Enabling ExtDesktopSize protocol extension for client ::1
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 Using raw encoding for client ::1
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 Sending rfbEncodingExtDesktopSize for size (2560x1440)
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 Sending rfbEncodingExtDesktopSize for size (2560x1440)
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xff09 "Tab") uip=1  23.2665
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xffe1 "Shift_L") uip=1  23.2665
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xffe2 "Shift_R") uip=1  23.2665
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xffe3 "Control_L") uip=1  23.2665
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xffe4 "Control_R") uip=1  23.2665
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xff09 "Tab") uip=1  23.2665
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xffe9 "Alt_L") uip=1  23.2665
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xff09 "Tab") uip=1  23.2666
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xffea "Alt_R") uip=1  23.2666
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xff09 "Tab") uip=1  23.2666
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xff09 "Tab") uip=1  23.3535
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xffe1 "Shift_L") uip=1  23.3535
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xffe2 "Shift_R") uip=1  23.3535
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xffe3 "Control_L") uip=1  23.3535
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xffe4 "Control_R") uip=1  23.3535
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xff09 "Tab") uip=1  23.3535
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xffe9 "Alt_L") uip=1  23.3535
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xff09 "Tab") uip=1  23.3535
Aug 20 17:52:22 mvc x11vnc[496042]: 20/08/2024 17:52:22 # keyboard(up, 0xffea "Alt_R") uip=1  23.3536

Also opened a bug report on xrdp neutrinolabs/xrdp#3216 , they suggest the issue may be on x11vnc side.
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Expected Behavior
User can input login info.

Screenshots

Desktop (please complete the following information):

• Xfce

Additional context