There are various considerations for gestures under Windows when UPDD is installed.
The performed gesture will be received by the driver as raw stylus co-ordinates.
Where the UPDD driver is in control of posting the touch data into the OS, it will simply deliver the raw data to the virtual device configured for the touch screen. If this is the Virtual HID touch device, then Windows will receive and process the gesture within the operating system.
In all cases, the touch data is posted on the UPDD API so that any UPDD Client applications receive the data.
If UPDD Commander is installed. (which is also a UPDD client application), it will disable the driver from directly posting the data to the OS and will receive the touch data and calculate the gesture being performed and invoke any action configured for that gesture. It can also be configured to post data back to the driver for onward dispatch to the OS.
Commander also posts the calculated gesture data back to the driver for onward dispatch to UPDD Client applications, as described here.
Native Windows gesture support
Most Windows editions of Window 7,8 and 10 supports gestures as part of the native touch support built into Windows. Native touch support is enabled when a compatible HID touch device is detected on the system. When UPDD is installed it creates a Virtual HID touch device (for each monitor connected to the system) such that Windows native touch support is enabled.