--- a/mail/installer/windows/nsis/defines.nsi.in
+++ b/mail/installer/windows/nsis/defines.nsi.in
@@ -1,10 +1,18 @@
 #filter substitution
+
+# Win7: AppVendor, AppName, and AppVersion must match the application.ini values
+# of Vendor, Name, and Version. These values are used in registering shortcuts
+# with the taskbar. ExplicitAppUserModelID registration when the app launches is
+# handled in widget/src/windows/WinTaskbar.cpp.
+# Note - Thunderbird does not set a Vendor in application.ini!
+!define AppName               "Thunderbird"
 !define AppVersion            "@MOZ_APP_VERSION@"
+!define AppUserModelID        "${AppName}.${AppVersion}"
 !define GREVersion            @MOZILLA_VERSION@
 !define AB_CD                 "@AB_CD@"
 
 !define FileMainEXE           "@MOZ_APP_NAME@.exe"
 !define WindowClass           "ThunderbirdMessageWindow"
 
 !define AppRegNameMail        "Thunderbird"
 !define AppRegNameNews        "Thunderbird (News)"

--- a/mail/installer/windows/nsis/uninstaller.nsi
+++ b/mail/installer/windows/nsis/uninstaller.nsi
@@ -99,16 +99,17 @@ VIAddVersionKey "OriginalFilename" "help
 !insertmacro FindSMProgramsDir
 !insertmacro GetLongPath
 !insertmacro GetPathFromString
 !insertmacro IsHandlerForInstallDir
 !insertmacro RegCleanMain
 !insertmacro RegCleanUninstall
 !insertmacro SetBrandNameVars
 !insertmacro UnloadUAC
+!insertmacro UpdateShortcutAppModelIDs
 !insertmacro WriteRegDWORD2
 !insertmacro WriteRegStr2
 
 !insertmacro un.ChangeMUIHeaderImage
 !insertmacro un.CheckForFilesInUse
 !insertmacro un.CleanUpdatesDir
 !insertmacro un.CleanVirtualStore
 !insertmacro un.DeleteShortcuts

--- a/suite/installer/windows/nsis/defines.nsi.in
+++ b/suite/installer/windows/nsis/defines.nsi.in
@@ -1,10 +1,19 @@
 #filter substitution
+
+# Win7: AppVendor, AppName, and AppVersion must match the application.ini values
+# of Vendor, Name, and Version. These values are used in registering shortcuts
+# with the taskbar. ExplicitAppUserModelID registration when the app launches is
+# handled in widget/src/windows/WinTaskbar.cpp.
+
+!define AppVendor             "Mozilla"
+!define AppName               "SeaMonkey"
 !define AppVersion            "@MOZ_APP_VERSION@"
+!define AppUserModelID        "${AppVendor}.${AppName}.${AppVersion}"
 !define GREVersion            @MOZILLA_VERSION@
 !define AB_CD                 "@AB_CD@"
 !define FileInstallerEXE      "@PKG_INST_BASENAME@.exe"
 !define FileInstallerMSI      "@PKG_INST_BASENAME@.msi"
 !define FileInstallerNETRoot  "@PKG_BASENAME@.net-installer"
 !define NO_UNINSTALL_SURVEY
 
 !define FileMainEXE           "@MOZ_APP_NAME@.exe"

--- a/suite/installer/windows/nsis/uninstaller.nsi
+++ b/suite/installer/windows/nsis/uninstaller.nsi
@@ -97,16 +97,17 @@ VIAddVersionKey "OriginalFilename" "help
 !insertmacro FindSMProgramsDir
 !insertmacro GetLongPath
 !insertmacro GetPathFromString
 !insertmacro IsHandlerForInstallDir
 !insertmacro RegCleanMain
 !insertmacro RegCleanUninstall
 !insertmacro SetBrandNameVars
 !insertmacro UnloadUAC
+!insertmacro UpdateShortcutAppModelIDs
 !insertmacro WordReplace
 !insertmacro WriteRegDWORD2
 !insertmacro WriteRegStr2
 
 !insertmacro un.ChangeMUIHeaderImage
 !insertmacro un.CheckForFilesInUse
 !insertmacro un.CleanUpdatesDir
 !insertmacro un.CleanVirtualStore