The "problem" is that in order for them to appear on the top panel, the application must be made especially for eOS. Dev want everyone to program apps exclusively for eOS...
The solution to this is install a third party application.
You'll need the following dependencies :
sudo apt-get install libglib2.0-dev libgranite-dev libindicator3-dev
sudo apt-get install libwingpanel-dev indicator-application
now install this:
Edit the file
sudo nano /etc/xdg/autostart/indicator-application.desktop
Search the parameter:
OnlyShowIn= and add "Pantheon" at the end of the line :
Save your changes with Ctrl+O then Ctrl+x to exit
After do all this, just reboot and enjoy eOS
If this solves your question don't forget to mark as solved