From Xojo Documentation
When set to False, hides system-wide UI, such as the Dock on Mac or the Start menu and taskbar on Windows. Defaults to True.
The behavior of this properties varies by OS. This is the behavior on current OS's (macOS Sierra, Windows 10, Linux Mint):
- Mac: When False (or OFF), the Dock and main menu bar are hidden when the window is frontmost.
- Windows: When False (or OFF), the taskbar (including "Start" button) is hidden, regardless of whether your app is frontmost.
- Linux Mint: When False (or OFF), the window menu bar is hidden (other distributions may have different behavior).