two qt ui header file namespace issue - c++

Question

I have two ui header - ui_FlowChartEditor.h and ui_Notepad.h
There was a problem with this codes :
//ui_FlowChartEditor.h
namespace Ui {
class FlowChartEditorClass: public Ui_FlowChartEditorClass {};
} // namespace Ui
//ui_Notepad.h
namespace Ui {
class NotepadClass: public Ui_NotepadClass {};
} // namespace Ui
'Ui' namespace was duplicated, so I solve this problem by changing name of namespace.
like this :
//ui_FlowChartEditor.h
namespace Ui_FlowChartEditor {
class FlowChartEditorClass: public Ui_FlowChartEditorClass {};
} // namespace Ui
//ui_Notepad.h
namespace Ui_Notepad {
class NotepadClass: public Ui_NotepadClass {};
} // namespace Ui
It works at Debug configuration, but not at Release configuration.
Compiler says : [error C2653: 'Ui_FlowChartEditor': is not a class or namespace name (compiling source file FlowChartEditor.cpp)], etc..
Is there any solution to solve this problem?
Thanks in advance.
With #zgyarmati's solution, I solved this problem.
I changed objectName in Qt Designer.
ui_ header file became like this:
namespace FlowChartEditorUi {
namespace Ui {
class FlowChartEditorClass : public Ui_FlowChartEditorClass {};
} // namespace Ui
} // namespace FlowChartEditorUi
Thx.

Answer 1

The ui_*.h files are regenerated by uic from your forms (.ui) files. You changed the generated ui_*.h files only for the debug build, but not for the release build, so you have the pristine, uic-generated files there.
You could change the files also for the release build, but
you are not supposed to change the generated files, as they will be overwritten.
To set a namespace for your ui class, when you are creating a Designer Form Class in QtCreator, specify a name with a namespace, e.g. Ui_Notepad::NotepadClass in the "Class name" field, and the generated ui_*.h file will contain that namespace.
If you already have your forms, then you can also change the "objectName" property for them accordingly in the QtCreator form editor.