Let say you want to change native os application, desktop application was writeln using QT framework.
At the time of writing this document desktop app is compatible with 4.8 QT 5.x QT version. For compiling on windows I use.
http://qt-project.org/downloads (Qt 5.2.1 for Windows 32-bit (MinGW 4.8, OpenGL, 634 MB))
Desktop client source can be found at
https://github.com/LiveHelperChat/desktop
With install comes Qt Creator application which should be used to compile application. So just run it and open lhc.pro file
Developing application takes a lot of time. You can support application by donating. There is no company behind this application and it takes away my free time. Every donation matters and does not matter how small it is!