Qmodbus crash when adding serial ports after starting and then change baudrate

[cedric-airsupplies]

Qmodbus crashes after it has been started without serial ports, then serial ports are added, and then the baudrate is changed.

Steps to reproduce:
0) Unplug all USB to serial ports dongles, so the PC doesn't have serial ports anymore.

1. Start qmodbus. this yields the message "Could not find any serial port on this computer." This is correct
2. Click ok. Now the main user interface of Qmodbus comes up.
3. Connect 2 USB to serial converters to the PC
4. Choose 9600 from the baudrate drop down box. Now I briefly see a activity marker with my mouse, and then qmodbus dissapears.
5. remove all usb to serial converters again.
6. Start qmodbus. this yields the message "Could not find any serial port on this computer." This is correct
7. Click ok. Now the main user interface of Qmodbus comes up.
8. connect one usb to serial converter.
9. Choose 9600 from the baudrate drop down box. Now I briefly see a activity marker with my mouse, and then qmodbus dissapears.

My versions:
QModBus 0.2.1
Windows 10 Home 21H2 19044.3086