diff --git a/include/CLI/StringTools.hpp b/include/CLI/StringTools.hpp
index d27204dd..f1aa04b5 100644
--- a/include/CLI/StringTools.hpp
+++ b/include/CLI/StringTools.hpp
@@ -108,7 +108,7 @@ std::string trim_copy(const std::string &str) {
 /// Make a copy of the string and then trim it, any filter string can be used (any char in string is filtered)
 std::string trim_copy(const std::string &str, const std::string &filter) {
     std::string s = str;
-    return rtrim(s, filter);
+    return trim(s, filter);
 }
 /// Print a two part "help" string
 void format_help(std::stringstream &out, std::string name, std::string description, size_t wid) {
diff --git a/tests/HelpersTest.cpp b/tests/HelpersTest.cpp
index f0a59fb6..d8580fce 100644
--- a/tests/HelpersTest.cpp
+++ b/tests/HelpersTest.cpp
@@ -62,6 +62,23 @@ TEST(Trim, VariousFilters) {
     EXPECT_EQ("cabcabc", CLI::detail::trim(s4, "ab"));
 }
 
+TEST(Trim, TrimCopy) {
+    std::string orig{" cabc  "};
+    std::string trimmed = CLI::detail::trim_copy(orig);
+    EXPECT_EQ("cabc", trimmed);
+    EXPECT_NE(orig, trimmed);
+    CLI::detail::trim(orig);
+    EXPECT_EQ(trimmed, orig);
+
+    orig = "abcabcabc";
+    trimmed = CLI::detail::trim_copy(orig, "ab");
+    EXPECT_EQ("cabcabc", trimmed);
+    EXPECT_NE(orig, trimmed);
+    CLI::detail::trim(orig, "ab");
+    EXPECT_EQ(trimmed, orig);
+
+}
+
 
 TEST(Validators, FileExists) {
     std::string myfile{"TestFileNotUsed.txt"};