fix trigger of shutdown sequence when last window is closed
fix trigger of shutdown sequence when last window is closed

shemnon/griffon,breskeby/griffon,tschulte/griffon,codehaus/griffon-git,griffon/griffon,tschulte/griffon,levymoreira/griffon,shemnon/griffon,breskeby/griffon,levymoreira/griffon,griffon/griffon,tschulte/griffon,codehaus/griffon-git,shemnon/griffon,levymoreira/griffon