The "Connect to Device" dialog accepts a driver selection, connection type and parameters (USB, serial, TCP), allows to scan for devices, and make the application use the selected and scanned device. The device to use must be selected from the result set of a scan attempt. The dialog allows to pick any of the connection types, but does not support the specification of "no connection type" (neither USB nor serial nor TCP). This prevents the scan for e.g. the Demo device. A (non-obvious for the unaware) workaround is to pick the Demo device from the triangle combobox that's "hidden" next to the button which opens the "Connect to Device" dialog.
> This prevents the scan for e.g. the Demo device. For me, leaving the connection type as USB finds the demo device just fine. Is that not the case for you?
Re-ran a test with PV as of b0319e16359d. Reproduces the issue. The "scan" result is empty for demo when USB is selected. Terminal output is: sr: hwdriver: Invalid option 'conn'. How to reproduce: Start pulseview with nothing connected, demo is found and used. Click on the "Demo device" combobox (the left side of it, not the triangle) which opens the "Connect to device" dialog. Select Demo, cannot de-select the connection type, stick with USB for example, press Scan and the result is empty. On second thought the triangle should reveal identical behaviour, just take a longer path to the dialog. VCS history suggests that 7a5535dc88a1 (fix for bug 1403) may also fix the issue reported here. Need to check (don't have a current setup available here, cherry-picking failed in a quick attempt). If current mainline works for you, and demo can get selected after using demo or something else before selecting demo, then feel free to close the report. Comments in bug 1403 suggest that other serial devices suffered from similar behaviour.
Fixed by the fix for #1403.