it's difficult to find the root cause without having the entire system on the table...
First of all, the provided Build Envrionment is prepared and tested with the GCC compiler in combination with the provided makefiles, startup code,... The Evaluatioin Edition of the STM32 Platform Package contains only libraries, that are compiled with GCC and the corresponding runtime libraries. Although it might be possible to link these libraries with other toolchains - the behaviour might be unpredictable...
The main idea of the Evaluation Edition is the familiarization with Embedded Wizard and its workflow. When you are using the Profdessional Edtion of Embedded Wizard Studio, you will get the source code of the Runtime Environment and the Graphics Engine, so it will be easy to compile and link everything with the toolchain of your choice. As long as you are working with the Evaluation Edition, we recommend to use the provided setting as it is.
See also 'using stm32 build environment with third party toolchain'.