keyboard navigation trap in device selection drop-down

When using the tab key to navigate within Pavucontrol, it is not possible to tab out of the device selection once it is focussed.

This issue came up in Pavucontrol 5, with ae278b86 .

Steps to reproduce

1. select the input or output tab.
2. use the tab key to navigate through the volume sliders and checkboxes until you focus a device selection drop-down.
3. Press tab or shift-tab again to move to the next element. Note this won't work

solution

in src/pavucontrol.glade change "can_focus" to "false", (see attached diff.) device_focus_trap.patch