Hi Félix -
I tested that here on 7.5 and 7.6 on my Mac and that seems to work. I just started Grasshopper, dropped a C# component on the canvas and then double-clicked. Is the issue file-specific on your side? If so, please post the Grasshopper file.
-wim
From what I can tell from that issue report (RH-63586), the fix went into 7.5 and the next public release candidate should be available tomorrow. If all goes well, that is.
-wim