Application crashes when trying to detect zones of other hetero nuclear 2D experiments than 1H-13C

@jobo322 @lpatiny If we want to do 2D zones picking (automatic or manual) on following file with nuclei 1H and 15N:

[https://github.com/cheminfo/nmr-displayer/tree/master/public/data/cytisine/2d/HMBC_HN_Cytisin.dx](url)

then the app crashes with following error:


But if we duplicate the file and replace the nucleus 15N by 13C everywhere, then it's working!

Here is the same but modified file with 1H-13C to test:

[pseudo_CN_HMBC_Cytisin.dx.zip](https://github.com/cheminfo/nmr-displayer/files/5770108/pseudo_CN_HMBC_Cytisin.dx.zip)

This issue I discovered also when trying to import other files like that one.

Same error occurs if we replace the 13C by 15N in a file which was working previously.