Finally, here comes the source code of lxpanel2, something developed for quite a long time but is never published online.

Browse the code: http://lxde.git.sourceforge.net/git/gitweb.cgi?p=lxde/lxpanel2;a=summary
The git repo:  git://lxde.git.sourceforge.net/gitroot/lxde/lxpanel2

To compile, you need cmake and vala.
The new version is re-written with vala + gtk3.
In the source code dir checked out from git repo, do this:

> mkdir build
> cd build
> cmake ..
> make
> sudo make install

Just like the old autotools, but cmake is way much faster and has nicer output.

Please, don't expect too much. It does not fully work yet.
Many things are still missing and some parts do not work at all.
Dynamically loadable applets are not correctly implemented yet.
I'm still thinking about a better way to make developing applet plugins easier.
Until I find out a better design, I'll continue finishing it.
Now I go back to fix remaining parts of the file manager pcmanfm/libfm. There has been some progress recently.
Unfortunately, I have a bad time working in the hospital recently and is really busy in March and April. :-(
Anyway, I'll keep doing this whenever possible.