Space key saves the current image on the desktop.
Try to reopen a disconnected camera automatically.
Try to save the current device state in the current working directory. If that fails, it is saved into %appdata% directory. This device.xml is loaded automatically at next program start, so the last used device is used again automatically.
In case a zoom camera is connected: Shift + mouse wheel zooms the lens in and out.
In case an auto focus camera is connected: Crtl + left mouse click executes auto focus.