Do not blindly insert ubound Alt-<letter> keybindings.

Fixes: #5575

diff --git a/src/frontends/qt4/GuiApplication.cpp b/src/frontends/qt4/GuiApplication.cpp
index 160df4a114d31fbbab41e73262a6850a36aed1b2..eaf33c44a23bfa68c425242414a8d1e97ca9a20b 100644 (file)
--- a/src/frontends/qt4/GuiApplication.cpp
+++ b/src/frontends/qt4/GuiApplication.cpp
@@ -2128,6 +2128,11 @@ void GuiApplication::processKeySym(KeySymbol const & keysym, KeyModifier state)
        }
 
        if (func.action() == LFUN_UNKNOWN_ACTION) {
+               if (state & AltModifier) {
+                       current_view_->message(_("Unknown function."));
+                       current_view_->restartCursor();
+                       return;
+               }
                // Hmm, we didn't match any of the keysequences. See
                // if it's normal insertable text not already covered
                // by a binding
@@ -2138,6 +2143,9 @@ void GuiApplication::processKeySym(KeySymbol const & keysym, KeyModifier state)
                                LYXERR(Debug::KEY, "Non-printable character! Omitting.");
                                return;
                        }
+                       // FIXME: Is this really needed? If not, we could  simply go with
+                       // with the else part for LFUN_UNKNOWN_ACTION
+                       // (see discussion at #5575)
                        LYXERR(Debug::KEY, "isText() is true, inserting.");
                        func = FuncRequest(LFUN_SELF_INSERT,
                                           FuncRequest::KEYBOARD);