Win8+ native spell checking requires compiling with Win8 target.

Win8-specific features are still loaded dynamically, so HC still works the same on W7.

win32/hexchat.props

@@ -65,6 +65,7 @@
 			<FunctionLevelLinking>true</FunctionLevelLinking>
 			<IntrinsicFunctions>true</IntrinsicFunctions>
 			<MultiProcessorCompilation>true</MultiProcessorCompilation>
+			<PreProcessorDefinitions>NTDDI_VERSION=NTDDI_WIN8;_WIN32_WINNT=_WIN32_WINNT_WIN8;%(PreProcessorDefinitions)</PreProcessorDefinitions>
 		</ClCompile>
 		<Lib>
 			<LinkTimeCodeGeneration>true</LinkTimeCodeGeneration>