Problem with intellisense VSCode

[sexypreneur]

So when I click Assets > Open C# project in Code. I see the intellisense working just fine.

But when I create C# script & double click to open up that script in Visual Studio Code & start writing code. Intellisense doesn't pop-up

What could be the reason?

How I'm using VSCode?
I'm using VSCode from Marketplace & whenever I create new project...I import the package. I'm not copying VSCode from Github to my Project's assets folder