You can enable and disable IntelliSense from the Edit menu. An additional quick way to disable IntelliSense is to click the appropriate button in the in the IntelliSense popup.
How to enable or disable IntelliSense from the Edit menu
Select Edit>IntelliSense>Enable IntelliSense.
If the option has a check mark next to it, IntelliSense is enabled. If the option does not have a check mark, IntelliSense is disabled.
How to disable IntelliSense from the popup
In the popup, click Disable IntelliSense.