In a previous version of the audio-output-switcher, the active output device could be selected from the drop-down, but now it is a label which cannot be selected. This had the benefit of moving all streams which have been "left behind" on another device before the system was rebooted over to the current stream.
This feature can be achieved by regressing to the old drop-down style, or by adding an option to Reset All Streams to the current audio device.
Another way to achieve this effect is to monitor for new streams and move them automatically over to the current device, but this seems perhaps an overstep of what a user may desire, and more difficult to implement
Use case (a.k.a. the long reason why this would be nice)
The use case for this feature is as follows. When I move my desktop over to my television, the HDMI audio stream becomes the stream which I want all my programs to move to. I use the audio-output-switcher to achieve this. I often shut-down the PC while the TV is the active display, and the HDMI audio output as the active audio output stream. This means that, when I power my computer on again, and my audio and video output streams are both reverted-to-default to my main monitor and speakers, any programs that were running "last night" are outputting their audio to the TV, which I cannot hear. In prior versions of the audio-output-switcher, I would just click the drop-down and select the active audio device. Currently, I have to select another audio device, and then open the panel again and select the current audio device. This means I have to suspend any videos that I'm watching so that I don't miss segments of audio. Hence why I'd appreciate the feature/regression!