Caught in 5.3 0180 preview, but also present in 5.2 stable.
I had Shift pressed while typing by mistake, making a “-1” read “_1”, resulting in crashing vvvv as shown below. Just checked “?” as input, which doesn’t break … not sure if there are any other special characters it might not catch, but it definitely doesn’t work for the Underscore.
Happens for all numerical IOBoxes (Float, Int, Int2 and all vector types).
