rqt: Could not find library corresponding to plugin

edit

Hello everyone ! I have been trying to make a simple GUI for my ros application using rqt. I am comfortable with Qt C++ but not really with ROS "advanced tools" (configurations, plugins, packages, etc...)

I tried to do the tutorial to build a simple "rqt_mypkg" in C++ and it works. Now I am trying to adapt this code to simply load a empty QWidget that I could modify later but so far I am always getting the same error:

[ERROR] [1477645407.408326805]: Failed to load nodelet [rescuer_project/MyWindow_1] of type [rescuer_project/MyWindow]: Could not find library corresponding to plugin rescuer_project/MyWindow. Make sure the plugin description XML file has the correct name of the library and that the library actually exists.

I checked mutiple times all of my files comparing to this example: rqt_example_cpp

There is definitely something I am not understanding... Probably related to "the way you name your plugin, and the name your class and package should have" I tried to make them all match like the example above but I am still getting the error.

Is using Python the only way to use rqt easily ?

Setup: Ubuntu 14, ROS indigo, Qt4 and Qt5 installed (Qt4 is default)

procedure used: catkin_make rqt --force-discover

This displays the recommended way of using rqt. Then when I click on my plugin's name I get the error mentionned above.

I am not using a *.ui file for my GUI, and I rather not to if possible.

The heading of my plugin.xml:

<class name="rescuer_project/MyWindow" type="rescuer_project::MyWindow" base_class_type="rqt_gui_cpp::Plugin">

Heading of my class:

        namespace rescuer_project {
    class MyWindow
            : public rqt_gui_cpp::Plugin
class declaration stuf...
...}

My repository with all code.

Thank you for helping !