Add TryExec to desktop files.

menu/applications/audacity.desktop

@@ -15,6 +15,7 @@ Type=Application
 Categories=AudioVideo;Audio;AudioVideoEditing;
 
 Exec=audacity
+TryExec=audacity
 StartupNotify=false
 Terminal=false
 MimeType=application/ogg;audio/basic;audio/mpeg;audio/x-aiff;audio/x-mp3;audio/x-wav;application/x-audacity-project;

menu/applications/celestia.desktop

@@ -5,6 +5,7 @@ GenericName=Space simulation
 Encoding=UTF-8
 Comment=A real-time visual space simulation
 Exec=celestia %f
+TryExec=celestia %f
 Terminal=false
 Icon=celestia
 Type=Application

menu/applications/dropbox.desktop

@@ -4,6 +4,7 @@ Name[ru]=Синхронизация файлов Dropbox
 GenericName=File Synchronizer
 Comment=Sync your files across computers and to the web
 Exec=dropbox-wrapper
+TryExec=dropbox-wrapper
 Terminal=false
 Type=Application
 Icon=dropbox

menu/applications/gcompris-edit.desktop

@@ -6,6 +6,7 @@ GenericName[ru]=Административный интерфейс
 Comment=Administration for gcompris
 Comment[ru]=Административный интерфейс для gcompris
 Exec=gcompris -a --nolockcheck
+TryExec=gcompris -a --nolockcheck
 Icon=gcompris-edit
 Terminal=false
 Type=Application

menu/applications/gcompris.desktop

@@ -43,6 +43,7 @@ GenericName[vi]=Trò chơi giáo dục đa hoạt động
 GenericName[zh_CN]=多样的教育游戏
 Comment=Educational game for ages 2 to 10
 Exec=gcompris
+TryExec=gcompris
 Icon=gcompris
 Terminal=false
 Type=Application

menu/applications/homebank.desktop

@@ -113,6 +113,7 @@ Comment[zh_CN]=免费，易用的个人财务软件。
 Comment[zh_HK]=費用全免，容易上手，全能的個人帳目
 Comment[zh_TW]=讓每個人都能自由、簡易的進行個人財務管理。
 Exec=homebank %F
+TryExec=homebank %F
 Terminal=false
 StartupNotify=true
 Type=Application

menu/applications/shotwell.desktop

@@ -5,6 +5,7 @@ Name[ru]=Программа управления фотографиями Shotwe
 GenericName=Photo Manager
 Comment=Organize your photos
 Exec=shotwell %U
+TryExec=shotwell %U
 Icon=shotwell
 Terminal=false
 Type=Application

menu/applications/synfigstudio.desktop

@@ -3,6 +3,7 @@ Name=Synfig Studio
 Name[ru]=Программа для создания 2D анимации Synfig Studio
 Comment=Create and edit 2D animations and compositions
 Exec=synfigstudio %F
+TryExec=synfigstudio %F
 Terminal=false
 Type=Application
 Icon=synfig_icon

menu/applications/timidity.desktop

@@ -3,6 +3,7 @@ Name=TiMidity++
 Name[ru]=MIDI-плеер TiMidity++
 Icon=timidity
 Exec=timidity -igt
+TryExec=timidity -igt
 Comment=A midi to wav converter and midi file player
 Comment[de]=Ein Midi-zu-Wav-Konverter und Midi-Player
 Comment[ru]=Плейер/конвертор MIDI-файлов

menu/applications/xfce4-about.desktop

@@ -2,6 +2,7 @@
 Version=1.0
 Type=Application
 Exec=xfce4-about
+TryExec=xfce4-about
 Icon=xfce4-panel-menu
 StartupNotify=false
 Terminal=false