diff --git a/MissionEditor/IniFile.h b/MissionEditor/IniFile.h
index d3b5c5d..4e552ee 100644
--- a/MissionEditor/IniFile.h
+++ b/MissionEditor/IniFile.h
@@ -172,14 +172,17 @@ public:
 
 	void RemoveAt(size_t idx) {
 		ASSERT(idx < value_pairs.size());
-		for (auto affectedIdx = idx + 1; affectedIdx < value_pairs.size(); ++affectedIdx) {
+		// delete from record first;
+		auto const& pair = value_pairs.at(idx);
+		ASSERT(value_pos.erase(pair.first) == 1);
+		value_pairs.erase(value_pairs.begin() + idx);
+		// now update all key-pos indexing, dec 1
+		for (auto affectedIdx = idx; affectedIdx < value_pairs.size(); ++affectedIdx) {
 			auto const& kvPair = value_pairs[affectedIdx];
 			auto const it = value_pos.find(kvPair.first);
 			ASSERT(it != value_pos.end());
 			it->second--;
 		}
-		auto const itErased = value_pairs.erase(value_pairs.begin() + idx);
-		ASSERT(value_pos.erase(itErased->first) == 1);
 	}
 
 	void RemoveByKey(const CString& key) {
diff --git a/UnitTest/CIni_Test.cpp b/UnitTest/CIni_Test.cpp
index 8c261e9..c22031b 100644
--- a/UnitTest/CIni_Test.cpp
+++ b/UnitTest/CIni_Test.cpp
@@ -137,3 +137,104 @@ Count=10
 	EXPECT_EQ(false, file.GetBool("Debug", "DisplayAllOverlay"));
 }
 
+TEST(CIniFileClass, IniAddSectionTest) {
+	auto const fileName = "test.ini";
+	IniTestHelper helper(fileName, R"(
+[SlopeSetPiecesDirections]
+Count=10
+0=Right_1
+1=Left_1
+2=Top_1
+3=Bottom_1
+4=Right_2
+5=Left_2
+6=Left_2
+7=Bottom_2
+8=Top_2
+9=Top_2
+)");
+
+	CIniFile file;
+	ASSERT_EQ(file.LoadFile(std::string(fileName)), 0);
+	file.AddSection("Debug");
+	auto pDebugSec = file.TryGetSection("Debug");
+	ASSERT_NE(pDebugSec, nullptr);
+	pDebugSec->SetBool("DisplayAllOverlay", false);
+	pDebugSec->SetBool("AllowTunnels", true);
+	EXPECT_EQ(true, file.GetBool("Debug", "AllowTunnels"));
+	EXPECT_EQ(false, file.GetBool("Debug", "DisplayAllOverlay"));
+}
+
+TEST(CIniFileClass, IniDeleteSectionTest) {
+	auto const fileName = "test.ini";
+	IniTestHelper helper(fileName, R"(
+[LUNARLimits]
+TreeMax=999
+TreeMin=999
+
+[URBANLimits]
+TreeMax=999
+;TreeMax=27
+
+[TEMPERATELimits]
+TreeMax=999
+;TreeMax=27
+
+[SNOWLimits]
+TreeMax=999
+;TreeMax=27
+
+[NEWURBANLimits]
+TreeMax=999
+;TreeMax=27
+
+[DESERTLimits]
+TreeMin=30
+TreeMax=999
+)");
+
+	CIniFile file;
+	ASSERT_EQ(file.LoadFile(std::string(fileName)), 0);
+
+	EXPECT_EQ(999, file.GetInteger("SNOWLimits", "TreeMax"));
+	EXPECT_EQ(999, file.GetInteger("LUNARLimits", "TreeMin"));
+
+	EXPECT_EQ(6, file.Size());
+	file.DeleteSection("SNOWLimits");
+
+	EXPECT_EQ(0, file.GetInteger("SNOWLimits", "TreeMax"));
+	EXPECT_EQ(nullptr, file.TryGetSection("SNOWLimits"));
+	EXPECT_EQ(5, file.Size());
+}
+
+TEST(CIniFileClass, IniDeleteValueTest) {
+	auto const fileName = "test.ini";
+	IniTestHelper helper(fileName, R"(
+[LUNARLimits]
+TreeMax=999
+TreeMin=999
+
+[NewUrbanInfo]
+Morphable2=114
+Ramps2=117
+Cliffs2=110
+CliffsWater2=112
+
+; tileset ini overwritings
+; only used by FinalAlert
+[IgnoreSetTEMPERATE]
+0=77
+1=78
+2=79
+)");
+
+	CIniFile file;
+	ASSERT_EQ(file.LoadFile(std::string(fileName)), 0);
+
+	EXPECT_EQ(114, file.GetInteger("NewUrbanInfo", "Morphable2"));
+	file.RemoveValueByKey("NewUrbanInfo", "Morphable2");
+
+	EXPECT_EQ(0, file.GetInteger("NewUrbanInfo", "Morphable2"));
+	EXPECT_EQ(false, file["NewUrbanInfo"].Exists("Morphable2"));
+
+}
\ No newline at end of file
diff --git a/UnitTest/UnitTest.vcxproj b/UnitTest/UnitTest.vcxproj
index 9b9ec94..76b6c5c 100644
--- a/UnitTest/UnitTest.vcxproj
+++ b/UnitTest/UnitTest.vcxproj
@@ -107,6 +107,7 @@
       <AdditionalIncludeDirectories>$(SolutionDir)googletest\x64\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <PrecompiledHeader>Create</PrecompiledHeader>
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
+      <LanguageStandard>stdcpp20</LanguageStandard>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>