Bug#959395: remmina: Grab all keyboard events not working after upgrade

[Bin Guo <gb2312@verizon.net>]

Package: remmina
Version: 1.4.2+dfsg-1
Severity: important

Dear Maintainer,

After upgrading remmina from 1.4.2+dfsg-1 to 1.4.3+dfsg-2 (plus
dependencies), Alt-Tab key in remote viewer keeps being processed by
host, while after downgrading back to 1.4.2+dfsg-1, Alt-Tab works in
remote viewer without problem.

Grab all keyboard events was enabled all the time, and I saw the same
problem with other hotkeys defined in host.

-- System Information:
Debian Release: bullseye/sid
  APT prefers oldstable-updates
  APT policy: (500, 'oldstable-updates'), (500, 'testing'), (500, 'oldstable'), (400, 'unstable'), (300, 'stable'), (200, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.5.0-2-amd64 (SMP w/4 CPU cores)
Kernel taint flags: TAINT_FIRMWARE_WORKAROUND
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8), LANGUAGE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages remmina depends on:
ii  dbus-user-session [default-dbus-session-bus]  1.12.16-2
ii  dbus-x11 [dbus-session-bus]                   1.12.16-2
ii  libavahi-client3                              0.7-5
ii  libavahi-common3                              0.7-5
ii  libavahi-ui-gtk3-0                            0.7-5
ii  libayatana-appindicator3-1                    0.5.4-2
ii  libc6                                         2.30-4
ii  libcairo2                                     1.16.0-4
ii  libgcrypt20                                   1.8.5-5
ii  libglib2.0-0                                  2.64.2-1
ii  libgtk-3-0                                    3.24.18-1
ii  libjson-glib-1.0-0                            1.4.4-2
hi  libpango-1.0-0                                1.42.4-8
ii  libsodium23                                   1.0.18-1
ii  libsoup2.4-1                                  2.70.0-1
ii  libssh-4                                      0.9.4-1
ii  libssl1.1                                     1.1.1g-1
ii  libvte-2.91-0                                 0.60.1-1
hi  remmina-common                                1.4.2+dfsg-1

Versions of packages remmina recommends:
hi  remmina-plugin-rdp     1.4.2+dfsg-1
hi  remmina-plugin-secret  1.4.2+dfsg-1
hi  remmina-plugin-vnc     1.4.2+dfsg-1

Versions of packages remmina suggests:
pn  remmina-plugin-exec     <none>
pn  remmina-plugin-kwallet  <none>
hi  remmina-plugin-nx       1.4.2+dfsg-1
hi  remmina-plugin-spice    1.4.2+dfsg-1
pn  remmina-plugin-www      <none>
hi  remmina-plugin-xdmcp    1.4.2+dfsg-1

-- no debconf information