Win/Super key not working correctly under Windows hosts

Host environment

• Operating system: Windows 11 Pro
• OS/kernel version: 23H2 22631.3447
• Architecture: x86_64
• QEMU flavor: qemu-system-i386, qemu-system-x86_64
• QEMU version: QEMU emulator version 9.0.0 (from qemu-9.0.0.tar.xz)
• QEMU command line:

Fedora 39

qemu-system-x86_64.exe -nodefaults -display sdl,gl=on -M q35,accel=whpx -m 3G -L share\OVMF -bios OVMF.fd -cpu Cascadelake-Server,-vmx,-monitor -device virtio-vga-gl -device qemu-xhci -device usb-tablet -device usb-kbd -cdrom "E:\Fedora-Workstation-Live-x86_64-39-1.5.iso"

WinXP

qemu-system-i386.exe -nodefaults -display sdl -M pc -m 1024M -accel whpx,kernel-irqchip=off -cpu qemu32 -device VGA -hda wxp.vhdx

Emulated/Virtualized environment

• Operating system: WinXP/Fedora 39
• OS/kernel version: WinXP SP3/ Fedora 39 6.5.6-300.fc39.x86_64
• Architecture: x86

Description of problem

I accidentally noticed Win key (VK_LWIN) not working correctly on Windows hosts, more specifically:

1. It is impossible to "hold" Win. If one presses and holds Win, the guest is spammed with Win keypresses, instead of receiving a single Win keypress at the point of releasing the button (VK_LWIN button up).
2. It is impossible to make key combinations (shortcuts, hotkeys etc.) that involve the Win/Super key. Maybe implicitly solved by fixing #1.

This behavior is present starting from bc8e8830 (ui/sdl2: disable SDL_HINT_GRAB_KEYBOARD on Windows). Before it, on the SDL2 keyboard hook Win/Super key worked correctly. I demonstrate the problem on Fedora/WinXP, but it affects all guests.

Steps to reproduce

1. (see additional information)

Additional information

Short video demonstration on a WinXP guest and a Fedora 39 guest. The qemus used are (qemu-8.0.2 e0968d21; working correctly) and (qemu-9.0.0 from the release tarball qemu-9.0.0.tar.xz; buggy)

1. In the WinXP video, I'm pressing and holding the Win key for about 3 seconds. In the correct version, the start menu is opened only at the point of release. In the buggy version, the start menu is opened repeatedly tens of times (flickering). You can see the point of release in Nirsoft's KeyboardStateView, when VK_LWIN loses the "pressed" asterisk.

   At the end of the video I'm trying to use the Win+e shortcut for WinExplorer. In the buggy version, Outlook is opened instead. This is because the keypresses are processed individually, first Win opens the start menu and then e opens email application (in this case outlook). In the correct version WinExplorer is opened.

   winxp-ok winxp-buggy

2. In the Fedora video, I'm trying to set up a simple shortcut, I'm pressing on my keyboard LCTRL+LALT+Super+E. In the buggy version, the Super key is not picked up. All the shortcut combinations involving Super are therefore not working.

   fedora39-ok fedora39-buggy