This could be caused by several different issues. Please check if the project can be built successfully. If not, please try creating a new project via VisualGDB Project Wizard and it will automatically get all the dependencies. If the build succeeds, but IntelliSense doesn’t work, please attach a screenshot of the entire Visual Studio window here and we can check for common problems.
Thanks for the update. We would definitely need to see the screenshots to advise you further. By “Entire Visual Studio Window” we mean the physical window created by Visual Studio (including the navigation bar, Solution Explorer and Errors pane). Those panes may contain clues to the problem and we would need to see them to understand which parts of the IntelliSense engine have been initialized properly.
Unfortunately as you have cropped the screenshot, hiding the navigation bar, we are not able to tell whether the Clang engine is properly attached to the source file. Please attach a screenshot of the entire VS window as requested above.
Also if the manual auto-completion (triggered by Ctrl+Space) works, but the automatic one doesn’t, please try clicking the lightning symbol in the auto-completion popup to enable the automatic mode.
The shortcut actually comes from Visual Studio. You can see under in Edit->IntelliSense together with a other IntelliSense commands. If you are not familiar with Visual Studio commands and shortcuts, we would advise looking through the Edit menu – it contains a few very powerful commands.