The reason the Bluetooth printing from mobile devices is taking long from Windows Mobile devices, is due to the fact that the mobile is first searching and then listing all available Bluetooth devices.
Setting the Default Printer
To prevent this, the next time an invoice is printed, select the checkbox "Always use this printer".

Resetting the Default Printer
Should you require to change the printer for some reason follow these steps:
- Select [Start / Programs / File Explorer]
- From the left drop down menu select "My Device", select the "Program Files" and then "Solid Sales Pro" folders
- Tap on the WMPrint application and uncheck the "Always use this printer"