The "SQL CE editor" do not ask to save when closing the window, nor it has a "Save" button (only a "save as")
v4.0.0.1
http://social.msdn.microsoft.com/Forums/vstudio/en-US/66e6d99e-dc39-4984-b8af-9f528f9f9042/how-do-you-cancel-a-toolwindowpane-or-visual-studio-ide-close-operation-via-a-vspackage?forum=vsx
http://geekswithblogs.net/onlyutkarsh/archive/2013/08/03/listening-to-tool-window-events-in-visual-studio.aspx
Comments: ** Comment from web user: ErikEJ **
v4.0.0.1
http://social.msdn.microsoft.com/Forums/vstudio/en-US/66e6d99e-dc39-4984-b8af-9f528f9f9042/how-do-you-cancel-a-toolwindowpane-or-visual-studio-ide-close-operation-via-a-vspackage?forum=vsx
http://geekswithblogs.net/onlyutkarsh/archive/2013/08/03/listening-to-tool-window-events-in-visual-studio.aspx
Comments: ** Comment from web user: ErikEJ **
@Brisa : What would be the best option when VS is closing - ignore unsaved documents or annoy the user with prompts to save?