Hi 
So you may be experiencing a dock issueā¦ 
It looks like GTK 2/3 apps are not closing from the dock / panel including the welcome app.
Solution:
Click an open area of your desktop and select wallpaper and screensaverā¦once the panel opens select screen saver from the toggle switch at the top that states wallpaper screensaver.
Click the desktop.
It will close in a fewā¦
