diff --git a/CHANGELOG.md b/CHANGELOG.md
index 37ffd9fc..9e40b4ef 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@
 
 - Completion, option `autoCallCompletion` did not work when using `textCompletion` in non-D sources.
 - Completion, does not allow `autoCallCompletion` when key modifiers are used, e.g <key>CTRL</key>+<key>Z</key>.
+- C/C++ highlighter was not set for _*.cxx_ files
 
 # v3.9.18
 
diff --git a/src/u_common.pas b/src/u_common.pas
index 18c44fb7..7ed74bec 100644
--- a/src/u_common.pas
+++ b/src/u_common.pas
@@ -1350,7 +1350,7 @@ function hasCppSyntax(const ext: string): boolean;
 begin
   result := false;
   case ext of
-    '.c', '.h', '.cc', '.cpp', '.hpp': result := true;
+    '.c', '.h', '.cc', '.cpp', '.hpp', '.cxx' : result := true;
   end;
 end;