ctrl + F8 macOS do not STOP BASIC execution?
I switched to my Windows 10 partition on my mac and I have tried the same with openMSX and with Windows 10 it does what is supposed to do a real MSX. Any help with macOS? Thanks in advance! 
Some environments have CTRL+F[n] globally bound. For example KDE uses CTRL+F[n] to switch to the n-th virtual desktop. Those key-combinations are intercepted globally and thus applications like openMSX never even see these key presses. In KDE I 'fixed' this by removing the global CTRL+F8 binding.
I'm not familiar with macOS, so I don't know if the above makes sense for macOS.
You are right. ctrl + F8 in my version of macOS HighSierra is binded to somethig about centering the menu status. I have disabled it and with the combination of fn + ctrl + f8 it does what is suposed to do! Thanks wouter_! 
Try Ctrl-Shift-F8 on the Mac. It should work.
I have an iMac late 2009 with a small keyboard. With my keyboard the combination has to be the fn key + ctrl + the f8 key.
Thaks for you comment 
Try Ctrl-Shift-F8 on the Mac. It should work.
Glad I've found this post. This was driving me crazy. I tried so many combinations, was playing with the console's bind command and nothing was working. The simple Ctrl+Shift+F8 works