Mate desktop: missing indicator icons

Question

I have Ubuntu 15.04 with all the latest updates on 64bit machine. I prefer to use Mate since it so far was the only desktop manager that did everything I wanted and did none of the things I do not like.

For some reason the indicator area in my panel only shows the volume indicator. There is no icon for the network-manager applet (but nm-applet is started!) there is not icon for the battery status, all other icons that were previously there are now gone.

There also seems to be no way to add an indicator applet for which of several configured keyboards should be used (previously there was an applet where I could select between en/es/de etc)

How could that happen and how can it be fixed?

The internet is unfortunately full with instructions which either do not apply (older versions etc) or make things worse.

Answer 1

The missing indicator icons were due to my own mistake: I confused the "notification area" applet with the "indicator applet". I added the three different versions of "indicator applet" which only show the volume indicator, if anything at all. However the "notification area" applet is the correct thing to add.

This applet now also shows the keyboard indicators like I want.

UPDATE: turns out that I have the same problem on a different computer now. Notification area is there but no keyboard layout indicator. Back to square 1.