Acrobat pro plante quand je veux modifier un formulaire

@Fabbien Are you using the old Classic interface or the new Acrobat interface? Sometimes the new Acrobat interface could be th culprit?! Try turning this off to see if this will do the trick, View-Disable new Acrobat. Acrobat will restart automatically. 

Also, you could try instead of right-clicking, how about using a keyboard shortcut Command E (MAC) or Control E (PC)—hopefully, this keyboard shortcut will open the Properties dialog box directly without causing a crash.