From Xojo Documentation
| This item was deprecated in version 2019r2.
Please use MenuItem.HasMacControlKey as a replacement.
| This property is only available on the macOS platform.
For cross-platform compatibility, use ＃If...＃Endif with the Target... specifiers to make sure you will not attempt to use this property on an incompatible platform.
The Control key on Macintosh. This property is Macintosh-only. If selected, the Control key must be held down while pressing the value of the Key property in order to trigger the event handler of the MenuItem.
Use MenuItem.KeyboardShortCut to change this value at runtime.