The interactive displays do not have a "freeze" feature like the Epson projectors.
Here are some alternatives.
- Extend your screen (instead of duplicating) and drag windows over when you want to show them
- Blank your screen using the "audio only" option
- Alt + Tab to switch between programs
- Control + 1 (2,3,4,etc...) to switch between tabs in Chrome
- Use "B" or "W" in PowerPoint to hide your content