I'm having trouble reproducing this on an upgrade Vivid install: when I click the Nautilus icon in the launcher I'm taken back to WS1 and the Nautilus window is in focus (all keyboard input is directed there).
I'm having trouble reproducing this on an upgrade Vivid install: when I click the Nautilus icon in the launcher I'm taken back to WS1 and the Nautilus window is in focus (all keyboard input is directed there).