Can't change .JNLP file association

Question

I cannot change the .JNLP file association.

When I try to change it (both with "open with..." and with Control Panel). When I choose the application javaws.exe (pictures below), nothing happens when I double click on it.

I even tried the cmd way, with the usual recommendation:

assoc .jnlp=JNLPFile
ftype JNLPFile="C:\Program Files\Java\jre1.8.0_221\bin\javaws.exe" "%1"*

But that doesn't work either.

VERY IMPORTANT If I drag any JNPL file on the program javaws.exe, it works !