Cannot read property 'type' of undefined

[pbadenski]

This happens when using handsontable library. When typing anything into a cell on each keystroke an exception gets thrown here:

Uncaught TypeError: Cannot read property 'type' of undefined
    at before (raven.js:886)
    at wrapped (raven.js:270)

Chrome: 55.0.2883.75 (64-bit)
Raven version used: 3.9.0
Handsontable version used: 0.29.0

[LewisJEllis]

Should be closed by #794, published in v3.9.1; give it a try and let us know if you run into any trouble.