diff --git a/Extension/src/common.ts b/Extension/src/common.ts
index 8817767b1..18fba33c0 100644
--- a/Extension/src/common.ts
+++ b/Extension/src/common.ts
@@ -165,19 +165,19 @@ export function getVcpkgRoot(): string {
 export function isHeaderFile(uri: vscode.Uri): boolean {
     const fileExt: string = path.extname(uri.fsPath);
     const fileExtLower: string = fileExt.toLowerCase();
-    return !fileExt || [".cuh", ".hpp", ".hh", ".hxx", ".h++", ".hp", ".h", ".ii", ".inl", ".idl", ""].some(ext => fileExtLower === ext);
+    return !fileExt || [".cuh", ".hpp", ".hh", ".hxx", ".h++", ".hp", ".h", ".inl", ".ipp", ".tcc", ".tlh", ".tli", ""].some(ext => fileExtLower === ext);
 }
 
 export function isCppFile(uri: vscode.Uri): boolean {
     const fileExt: string = path.extname(uri.fsPath);
     const fileExtLower: string = fileExt.toLowerCase();
-    return (fileExt === ".C") || [".cu", ".cpp", ".cc", ".cxx", ".c++", ".cp", ".ino", ".ipp", ".tcc"].some(ext => fileExtLower === ext);
+    return (fileExt === ".C") || [".cu", ".cpp", ".cc", ".cxx", ".c++", ".cp", ".ii", ".ino"].some(ext => fileExtLower === ext);
 }
 
 export function isCFile(uri: vscode.Uri): boolean {
     const fileExt: string = path.extname(uri.fsPath);
     const fileExtLower: string = fileExt.toLowerCase();
-    return (fileExt === ".C") || fileExtLower === ".c";
+    return fileExt === ".c" || fileExtLower === ".i";
 }
 
 export function isCppOrCFile(uri: vscode.Uri | undefined): boolean {