Comment 7 for bug 1618723

write, here goes,
press cont+alt+escape.
press control+f10
list of options will popup.
click delete panel I think it is called.
then try cont+alt+escape again if you don't see the wireless network icon, you may need to upgrade mate to the version stated
below.

if that option does not work, i.e the option delete this panel is not there, then try alt+f2 type mate-panel --replace
it may help.
i'm running mate- 1.14.1 on sonar gnu-linux not *buntu
there was a upgrade to mate-panel which fixed an issue wherein non of the applets were being spoken via orca.
don't know if this is the bugg.
how ever fixed here:

https://github.com/mate-desktop/mate-panel/issues/440#issuecomment-222367190
and yes, I am thee majid :D