Problem about using multi-target in a projrct

Hi,
I found a problem using multi-target in a project.

If I create 2 targets,and
1. in [Options for Target 'Target 1'] define APP1 in preprocessor symbols
2. in [Options for Target 'Target 2'] define APP2 in preprocessor symbols

and there is a c file in the project like:

version.c

#ifdef APP1
    const uint8_t Version[]="00000001";
#elif defined APP2
    const uint8_t Version[]="00000002";
#endif

Now if I build target1, and switch to target 2,then build this target using 'Bulid(F7)',the version.c will not be rebuild. So in the output HEX file, I can see the data of 'Version' is still "00000001".

After that I found if I use 'Rebuild' command,the output HEX file will be updated. But rebuild all takes too much time.

Is it a bug or not?