I think I've found it now. In v1.1.0 I refactored the scan code to allow me to write regression tests for almost everything using signals. However, it seems that changing the device via the device combobox didn't actually trigger the changed-device signal.
Please try this patch, which should fix things. If you can't work with the patch, then I can give you a .deb of a pre-release of the next version.
set_device.patch
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signature.asc
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