diff --git a/ChangeLog.asciidoc b/ChangeLog.asciidoc
index 92a98c5cd..2359fa155 100644
--- a/ChangeLog.asciidoc
+++ b/ChangeLog.asciidoc
@@ -15,6 +15,8 @@ http://weechat.org/files/releasenotes/ReleaseNotes-devel.html[release notes]
 
 == Version 1.0 (under dev)
 
+* core: display a warning on startup if $TERM is not screen(-256color) under
+  screen/tmux
 * core: add option "-mask" in command /unset (closes #112)
 * core: add option weechat.color.status_nicklist_count (closes #109,
   closes #110)
diff --git a/po/cs.po b/po/cs.po
index c3be78f65..3fdb43fef 100644
--- a/po/cs.po
+++ b/po/cs.po
@@ -20,8 +20,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2014-07-12 08:50+0200\n"
-"PO-Revision-Date: 2014-06-28 13:18+0200\n"
+"POT-Creation-Date: 2014-07-14 18:54+0200\n"
+"PO-Revision-Date: 2014-07-14 18:44+0200\n"
 "Last-Translator: Jiri Golembiovsky <golemj@gmail.com>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
 "Language: cs\n"
@@ -182,6 +182,17 @@ msgstr "Chyba: domovský adresář (%s) není adresářem\n"
 msgid "Error: cannot create directory \"%s\"\n"
 msgstr "Chyba: nemohu vytvořit adresář \"%s\"\n"
 
+#. TRANSLATORS: the "under %s" can be "under screen" or "under tmux"
+#, c-format
+msgid ""
+"%sWarning: WeeChat is running under %s and $TERM is \"%s\", which can cause "
+"display bugs; $TERM should be set to \"screen-256color\" or \"screen\""
+msgstr ""
+
+#, c-format
+msgid "%sYou should add this line in the file %s:  %s"
+msgstr ""
+
 msgid "List of bars:"
 msgstr "Seznam polí:"
 
@@ -10717,6 +10728,3 @@ msgstr "%s%s: nemohu nastavit \"neblokovaci\" volbu na soket"
 #, c-format
 msgid "%s%s: timeout for \"%s\" with %s"
 msgstr "%s%s: vypršel časový limit \"%s\" pro %s"
-
-#~ msgid "<option>"
-#~ msgstr "<volba>"
diff --git a/po/de.po b/po/de.po
index fa885ae86..86ca70c17 100644
--- a/po/de.po
+++ b/po/de.po
@@ -22,8 +22,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2014-07-12 08:50+0200\n"
-"PO-Revision-Date: 2014-06-29 12:38+0100\n"
+"POT-Creation-Date: 2014-07-14 18:54+0200\n"
+"PO-Revision-Date: 2014-07-14 18:44+0200\n"
 "Last-Translator: Nils Görs <weechatter@arcor.de>\n"
 "Language-Team: German <weechatter@arcor.de>\n"
 "Language: de_DE\n"
@@ -187,6 +187,17 @@ msgstr "Fehler: HOME (%s) ist kein Verzeichnis\n"
 msgid "Error: cannot create directory \"%s\"\n"
 msgstr "Fehler: Das Verzeichnis \"%s\" kann nicht anlegt werden\n"
 
+#. TRANSLATORS: the "under %s" can be "under screen" or "under tmux"
+#, c-format
+msgid ""
+"%sWarning: WeeChat is running under %s and $TERM is \"%s\", which can cause "
+"display bugs; $TERM should be set to \"screen-256color\" or \"screen\""
+msgstr ""
+
+#, c-format
+msgid "%sYou should add this line in the file %s:  %s"
+msgstr ""
+
 msgid "List of bars:"
 msgstr "Liste der vorhandenen Infobars:"
 
@@ -12087,15 +12098,3 @@ msgstr ""
 #, c-format
 msgid "%s%s: timeout for \"%s\" with %s"
 msgstr "%s%s: Zeitüberschreitung für \"%s\" mit %s"
-
-#~ msgid "<option>"
-#~ msgstr "<option>"
-
-#~ msgid "evaluate expression and send result to buffer"
-#~ msgstr "wertet eine Expression aus und zeigt das Resultat im Buffer an"
-
-#~ msgid "Passphrase"
-#~ msgstr "Passphrase"
-
-#~ msgid "Passphrase is NOT set"
-#~ msgstr "Passphrase ist NICHT festgelegt"
diff --git a/po/es.po b/po/es.po
index c20ddd68b..1aafce57c 100644
--- a/po/es.po
+++ b/po/es.po
@@ -22,8 +22,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2014-07-12 08:50+0200\n"
-"PO-Revision-Date: 2014-06-28 13:18+0200\n"
+"POT-Creation-Date: 2014-07-14 18:54+0200\n"
+"PO-Revision-Date: 2014-07-14 18:44+0200\n"
 "Last-Translator: Elián Hanisch <lambdae2@gmail.com>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
 "Language: es\n"
@@ -188,6 +188,17 @@ msgstr "Error: home (%s) no es un directorio\n"
 msgid "Error: cannot create directory \"%s\"\n"
 msgstr "Error: no es posible crear el directorio \"%s\"\n"
 
+#. TRANSLATORS: the "under %s" can be "under screen" or "under tmux"
+#, c-format
+msgid ""
+"%sWarning: WeeChat is running under %s and $TERM is \"%s\", which can cause "
+"display bugs; $TERM should be set to \"screen-256color\" or \"screen\""
+msgstr ""
+
+#, c-format
+msgid "%sYou should add this line in the file %s:  %s"
+msgstr ""
+
 msgid "List of bars:"
 msgstr "Lista de barras:"
 
@@ -11001,9 +11012,3 @@ msgstr "%s%s: no es posible configurar la opción \"nonblock\" para el socket"
 #, c-format
 msgid "%s%s: timeout for \"%s\" with %s"
 msgstr "%s%s: tiempo de espera máximo para \"%s\" con %s"
-
-#~ msgid "<option>"
-#~ msgstr "<opción>"
-
-#~ msgid "evaluate expression and send result to buffer"
-#~ msgstr "evaluar la expresión y enviar el resultado al buffer"
diff --git a/po/fr.po b/po/fr.po
index 1b772e5b2..5abd9bc55 100644
--- a/po/fr.po
+++ b/po/fr.po
@@ -21,8 +21,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2014-07-12 08:50+0200\n"
-"PO-Revision-Date: 2014-07-12 08:56+0200\n"
+"POT-Creation-Date: 2014-07-14 18:54+0200\n"
+"PO-Revision-Date: 2014-07-14 18:54+0200\n"
 "Last-Translator: Sébastien Helleu <flashcode@flashtux.org>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
 "Language: fr\n"
@@ -180,6 +180,20 @@ msgstr "Erreur : la base (%s) n'est pas un répertoire\n"
 msgid "Error: cannot create directory \"%s\"\n"
 msgstr "Erreur : impossible de créer le répertoire \"%s\"\n"
 
+#. TRANSLATORS: the "under %s" can be "under screen" or "under tmux"
+#, c-format
+msgid ""
+"%sWarning: WeeChat is running under %s and $TERM is \"%s\", which can cause "
+"display bugs; $TERM should be set to \"screen-256color\" or \"screen\""
+msgstr ""
+"%sAttention : WeeChat tourne sous %s et $TERM est \"%s\", ce qui peut poser "
+"des problèmes d'affichage ; $TERM devrait être égal à \"screen-256color\" ou "
+"\"screen\""
+
+#, c-format
+msgid "%sYou should add this line in the file %s:  %s"
+msgstr "%sVous devriez ajouter cette ligne dans le fichier %s:  %s"
+
 msgid "List of bars:"
 msgstr "Liste des barres :"
 
@@ -11837,9 +11851,3 @@ msgstr ""
 #, c-format
 msgid "%s%s: timeout for \"%s\" with %s"
 msgstr "%s%s : délai d'attente dépassé pour \"%s\" avec %s"
-
-#~ msgid "<option>"
-#~ msgstr "<option>"
-
-#~ msgid "evaluate expression and send result to buffer"
-#~ msgstr "évaluer une expression et envoyer le résultat au tampon"
diff --git a/po/hu.po b/po/hu.po
index 85a2bc028..bca967cce 100644
--- a/po/hu.po
+++ b/po/hu.po
@@ -20,8 +20,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2014-07-12 08:50+0200\n"
-"PO-Revision-Date: 2014-06-28 13:18+0200\n"
+"POT-Creation-Date: 2014-07-14 18:54+0200\n"
+"PO-Revision-Date: 2014-07-14 18:44+0200\n"
 "Last-Translator: Andras Voroskoi <voroskoi@frugalware.org>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
 "Language: hu\n"
@@ -183,6 +183,17 @@ msgstr ""
 msgid "Error: cannot create directory \"%s\"\n"
 msgstr "%s nem sikerült a \"%s\" könyvtárat létrehozni\n"
 
+#. TRANSLATORS: the "under %s" can be "under screen" or "under tmux"
+#, c-format
+msgid ""
+"%sWarning: WeeChat is running under %s and $TERM is \"%s\", which can cause "
+"display bugs; $TERM should be set to \"screen-256color\" or \"screen\""
+msgstr ""
+
+#, c-format
+msgid "%sYou should add this line in the file %s:  %s"
+msgstr ""
+
 #, fuzzy
 msgid "List of bars:"
 msgstr "Aliaszok listája:\n"
@@ -10104,7 +10115,3 @@ msgstr "%s DCC: nem sikerült 'nonblock' opciót beállítani a csatornán\n"
 #, fuzzy, c-format
 msgid "%s%s: timeout for \"%s\" with %s"
 msgstr "%s hiányzó argumentum a(z) \"%s\" opciónak\n"
-
-#, fuzzy
-#~ msgid "<option>"
-#~ msgstr "[parancs]"
diff --git a/po/it.po b/po/it.po
index d0f88cb75..f4c8347e7 100644
--- a/po/it.po
+++ b/po/it.po
@@ -20,8 +20,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2014-07-12 08:50+0200\n"
-"PO-Revision-Date: 2014-06-28 14:49+0200\n"
+"POT-Creation-Date: 2014-07-14 18:54+0200\n"
+"PO-Revision-Date: 2014-07-14 18:44+0200\n"
 "Last-Translator: Esteban I. Ruiz Moreno <exio4.com@gmail.com>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
 "Language: it\n"
@@ -179,6 +179,17 @@ msgstr "Errore: home (%s) non è una directory\n"
 msgid "Error: cannot create directory \"%s\"\n"
 msgstr "Errore: impossibile creare la directory \"%s\"\n"
 
+#. TRANSLATORS: the "under %s" can be "under screen" or "under tmux"
+#, c-format
+msgid ""
+"%sWarning: WeeChat is running under %s and $TERM is \"%s\", which can cause "
+"display bugs; $TERM should be set to \"screen-256color\" or \"screen\""
+msgstr ""
+
+#, c-format
+msgid "%sYou should add this line in the file %s:  %s"
+msgstr ""
+
 msgid "List of bars:"
 msgstr "Elenco delle barre:"
 
@@ -11172,9 +11183,3 @@ msgstr ""
 #, c-format
 msgid "%s%s: timeout for \"%s\" with %s"
 msgstr "%s%s: timeout per \"%s\" con %s"
-
-#~ msgid "<option>"
-#~ msgstr "<opzione>"
-
-#~ msgid "evaluate expression and send result to buffer"
-#~ msgstr "analizza l'espressione e invia il risultato al buffer"
diff --git a/po/ja.po b/po/ja.po
index 9f2337c5a..8f3ea362a 100644
--- a/po/ja.po
+++ b/po/ja.po
@@ -20,8 +20,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2014-07-12 08:50+0200\n"
-"PO-Revision-Date: 2014-07-06 10:54+0900\n"
+"POT-Creation-Date: 2014-07-14 18:54+0200\n"
+"PO-Revision-Date: 2014-07-14 18:44+0200\n"
 "Last-Translator: AYANOKOUZI, Ryuunosuke <i38w7i3@yahoo.co.jp>\n"
 "Language-Team: Japanese <https://github.com/l/weechat/tree/translation_ja>\n"
 "Language: ja\n"
@@ -177,6 +177,17 @@ msgstr "エラー: ホーム (%s) はディレクトリではありません\n"
 msgid "Error: cannot create directory \"%s\"\n"
 msgstr "エラー: ディレクトリ \"%s\" の作成に失敗しました\n"
 
+#. TRANSLATORS: the "under %s" can be "under screen" or "under tmux"
+#, c-format
+msgid ""
+"%sWarning: WeeChat is running under %s and $TERM is \"%s\", which can cause "
+"display bugs; $TERM should be set to \"screen-256color\" or \"screen\""
+msgstr ""
+
+#, c-format
+msgid "%sYou should add this line in the file %s:  %s"
+msgstr ""
+
 msgid "List of bars:"
 msgstr "バーのリスト:"
 
@@ -11385,9 +11396,3 @@ msgstr "%s%s: ソケットにオプション \"nonblock\" を設定できませ
 #, c-format
 msgid "%s%s: timeout for \"%s\" with %s"
 msgstr "%s%s: \"%s\" のタイムアウト %s"
-
-#~ msgid "<option>"
-#~ msgstr "<option>"
-
-#~ msgid "evaluate expression and send result to buffer"
-#~ msgstr "式を評価して結果をバッファに送信"
diff --git a/po/pl.po b/po/pl.po
index a4e2b96de..9954b210d 100644
--- a/po/pl.po
+++ b/po/pl.po
@@ -21,8 +21,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2014-07-12 08:50+0200\n"
-"PO-Revision-Date: 2014-06-28 14:49+0200\n"
+"POT-Creation-Date: 2014-07-14 18:54+0200\n"
+"PO-Revision-Date: 2014-07-14 18:44+0200\n"
 "Last-Translator: Krzysztof Korościk <soltys@szluug.org>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
 "Language: pl\n"
@@ -179,6 +179,17 @@ msgstr "Błąd: %s nie jest katalogiem\n"
 msgid "Error: cannot create directory \"%s\"\n"
 msgstr "Błąd: nie można utworzyć katalogu \"%s\"\n"
 
+#. TRANSLATORS: the "under %s" can be "under screen" or "under tmux"
+#, c-format
+msgid ""
+"%sWarning: WeeChat is running under %s and $TERM is \"%s\", which can cause "
+"display bugs; $TERM should be set to \"screen-256color\" or \"screen\""
+msgstr ""
+
+#, c-format
+msgid "%sYou should add this line in the file %s:  %s"
+msgstr ""
+
 msgid "List of bars:"
 msgstr "Lista pasków:"
 
@@ -11439,9 +11450,3 @@ msgstr "%s%s: nie można ustawić opcji \"nonblock\" dla gniazda: błąd %d %s"
 #, c-format
 msgid "%s%s: timeout for \"%s\" with %s"
 msgstr "%s%s: przekroczono czas na \"%s\" z %s"
-
-#~ msgid "<option>"
-#~ msgstr "<opcja>"
-
-#~ msgid "evaluate expression and send result to buffer"
-#~ msgstr "przetwarza wyrażenie i wysyła wynik do buforu"
diff --git a/po/pt_BR.po b/po/pt_BR.po
index 6086cb0de..b9ddc6848 100644
--- a/po/pt_BR.po
+++ b/po/pt_BR.po
@@ -21,8 +21,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2014-07-12 08:50+0200\n"
-"PO-Revision-Date: 2014-06-28 13:18+0200\n"
+"POT-Creation-Date: 2014-07-14 18:54+0200\n"
+"PO-Revision-Date: 2014-07-14 18:44+0200\n"
 "Last-Translator: Sergio Durigan Junior <sergiosdj@gmail.com>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
 "Language: pt_BR\n"
@@ -211,6 +211,17 @@ msgstr "Erro: (%s) não é um diretório\n"
 msgid "Error: cannot create directory \"%s\"\n"
 msgstr "Erro: não foi possível criar o diretório \"%s\"\n"
 
+#. TRANSLATORS: the "under %s" can be "under screen" or "under tmux"
+#, c-format
+msgid ""
+"%sWarning: WeeChat is running under %s and $TERM is \"%s\", which can cause "
+"display bugs; $TERM should be set to \"screen-256color\" or \"screen\""
+msgstr ""
+
+#, c-format
+msgid "%sYou should add this line in the file %s:  %s"
+msgstr ""
+
 msgid "List of bars:"
 msgstr "Lista de barras:"
 
@@ -10366,6 +10377,3 @@ msgstr "%s%s: não foi possível setar opção \"nonblock\" para o socket"
 #, c-format
 msgid "%s%s: timeout for \"%s\" with %s"
 msgstr "%s%s: tempo esgotado para \"%s\" com %s"
-
-#~ msgid "<option>"
-#~ msgstr "<opção>"
diff --git a/po/ru.po b/po/ru.po
index 8882293e7..a0db812aa 100644
--- a/po/ru.po
+++ b/po/ru.po
@@ -21,8 +21,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2014-07-12 08:50+0200\n"
-"PO-Revision-Date: 2014-06-28 13:18+0200\n"
+"POT-Creation-Date: 2014-07-14 18:54+0200\n"
+"PO-Revision-Date: 2014-07-14 18:44+0200\n"
 "Last-Translator: Aleksey V Zapparov AKA ixti <ixti@member.fsf.org>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
 "Language: ru\n"
@@ -192,6 +192,17 @@ msgstr "%s домашний каталог (%s) не является дирек
 msgid "Error: cannot create directory \"%s\"\n"
 msgstr "%s не могу создать директорию \"%s\"\n"
 
+#. TRANSLATORS: the "under %s" can be "under screen" or "under tmux"
+#, c-format
+msgid ""
+"%sWarning: WeeChat is running under %s and $TERM is \"%s\", which can cause "
+"display bugs; $TERM should be set to \"screen-256color\" or \"screen\""
+msgstr ""
+
+#, c-format
+msgid "%sYou should add this line in the file %s:  %s"
+msgstr ""
+
 #, fuzzy
 msgid "List of bars:"
 msgstr "Список сокращений:\n"
@@ -10125,7 +10136,3 @@ msgstr "%s DCC: не могу установить неблокирующий р
 #, fuzzy, c-format
 msgid "%s%s: timeout for \"%s\" with %s"
 msgstr "%s нет аргумента для параметра \"%s\"\n"
-
-#, fuzzy
-#~ msgid "<option>"
-#~ msgstr "[команда]"
diff --git a/po/tr.po b/po/tr.po
index 17ac11db6..2f8709e5e 100644
--- a/po/tr.po
+++ b/po/tr.po
@@ -20,8 +20,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2014-07-12 08:50+0200\n"
-"PO-Revision-Date: 2014-06-28 13:18+0200\n"
+"POT-Creation-Date: 2014-07-14 18:54+0200\n"
+"PO-Revision-Date: 2014-07-14 18:44+0200\n"
 "Last-Translator: Hasan Kiran <sunder67@hotmail.com>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
 "Language: tr\n"
@@ -154,6 +154,17 @@ msgstr ""
 msgid "Error: cannot create directory \"%s\"\n"
 msgstr "Hata: \"%s\" dizini oluşturulamaz\n"
 
+#. TRANSLATORS: the "under %s" can be "under screen" or "under tmux"
+#, c-format
+msgid ""
+"%sWarning: WeeChat is running under %s and $TERM is \"%s\", which can cause "
+"display bugs; $TERM should be set to \"screen-256color\" or \"screen\""
+msgstr ""
+
+#, c-format
+msgid "%sYou should add this line in the file %s:  %s"
+msgstr ""
+
 msgid "List of bars:"
 msgstr ""
 
@@ -9130,6 +9141,3 @@ msgstr ""
 #, c-format
 msgid "%s%s: timeout for \"%s\" with %s"
 msgstr ""
-
-#~ msgid "<option>"
-#~ msgstr "<seçenek>"
diff --git a/po/weechat.pot b/po/weechat.pot
index 00878cf7f..d03b30724 100644
--- a/po/weechat.pot
+++ b/po/weechat.pot
@@ -21,7 +21,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat 0.4.1-dev\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2014-07-12 08:50+0200\n"
+"POT-Creation-Date: 2014-07-14 18:54+0200\n"
 "PO-Revision-Date: 2013-02-14 18:20+0100\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -154,6 +154,17 @@ msgstr ""
 msgid "Error: cannot create directory \"%s\"\n"
 msgstr ""
 
+#. TRANSLATORS: the "under %s" can be "under screen" or "under tmux"
+#, c-format
+msgid ""
+"%sWarning: WeeChat is running under %s and $TERM is \"%s\", which can cause "
+"display bugs; $TERM should be set to \"screen-256color\" or \"screen\""
+msgstr ""
+
+#, c-format
+msgid "%sYou should add this line in the file %s:  %s"
+msgstr ""
+
 msgid "List of bars:"
 msgstr ""
 
diff --git a/src/core/wee-command.c b/src/core/wee-command.c
index 2e80ff648..b9fdf4ac3 100644
--- a/src/core/wee-command.c
+++ b/src/core/wee-command.c
@@ -1774,6 +1774,7 @@ COMMAND_CALLBACK(debug)
     if (string_strcasecmp (argv[1], "term") == 0)
     {
         gui_window_term_display_infos ();
+        weechat_term_check ();
         return WEECHAT_RC_OK;
     }
 
diff --git a/src/core/weechat.c b/src/core/weechat.c
index 50c8834cd..cd474711f 100644
--- a/src/core/weechat.c
+++ b/src/core/weechat.c
@@ -385,6 +385,50 @@ weechat_welcome_message ()
     }
 }
 
+/*
+ * Displays warnings about $TERM if it is detected as wrong.
+ *
+ * If $TERM is different from "screen" or "screen-256color" and that $STY is
+ * set (GNU screen) or $TMUX is set (tmux), then a warning is displayed.
+ */
+
+void
+weechat_term_check ()
+{
+    char *term, *sty, *tmux;
+    int is_term_ok, is_screen, is_tmux;
+
+    term = getenv ("TERM");
+    sty = getenv ("STY");
+    tmux = getenv ("TMUX");
+
+    is_term_ok = (term && ((strcmp (term, "screen") == 0)
+                           || (strcmp (term, "screen-256color") == 0)));
+    is_screen = (sty && sty[0]);
+    is_tmux = (tmux && tmux[0]);
+
+    if ((is_screen || is_tmux) && !is_term_ok)
+    {
+        gui_chat_printf (
+            NULL,
+            /* TRANSLATORS: the "under %s" can be "under screen" or "under tmux" */
+            _("%sWarning: WeeChat is running under %s and $TERM is \"%s\", "
+              "which can cause display bugs; $TERM should be set to "
+              "\"screen-256color\" or \"screen\""),
+            gui_chat_prefix[GUI_CHAT_PREFIX_ERROR],
+            (is_screen) ? "screen" : "tmux",
+            (term) ? term : "");
+        gui_chat_printf (
+            NULL,
+            _("%sYou should add this line in the file %s:  %s"),
+            gui_chat_prefix[GUI_CHAT_PREFIX_ERROR],
+            (is_screen) ? "~/.screenrc" : "~/.tmux.conf",
+            (is_screen) ?
+            "term screen-256color" :
+            "set -g default-terminal \"screen-256color\"");
+    }
+}
+
 /*
  * Shutdowns WeeChat.
  */
@@ -466,6 +510,7 @@ main (int argc, char *argv[])
     }
     weechat_welcome_message ();         /* display WeeChat welcome message  */
     gui_chat_print_lines_waiting_buffer (NULL); /* display lines waiting    */
+    weechat_term_check ();              /* warnings about $TERM (if wrong)  */
     command_startup (0);                /* command executed before plugins  */
     plugin_init (weechat_auto_load_plugins, /* init plugin interface(s)     */
                  argc, argv);
diff --git a/src/core/weechat.h b/src/core/weechat.h
index bea355892..8eee8079a 100644
--- a/src/core/weechat.h
+++ b/src/core/weechat.h
@@ -106,6 +106,7 @@ extern int weechat_no_gnutls;
 extern int weechat_no_gcrypt;
 extern char *weechat_startup_commands;
 
+extern void weechat_term_check ();
 extern void weechat_shutdown (int return_code, int crash);
 
 #endif /* WEECHAT_H */