You might be missing the “aggressive completion” option (press Ctrl+Space in the text editor and click on the lightning symbol in the completion popup to enable it). If this doesn’t help, please let us know more about what exactly do you expect/observe.
Generally, we advise using our Clang engine over the native VC++ one, as it’s specifically optimized for GCC-specific code and also provides various advanced features like create-from-use, CodeJumps, instant go-to-definition and mode. You can read more about the Clang IntelliSense highlights here: https://visualgdb.com/?features=intellisense