I normally use Gerbv to check my gerbers before sending them off. However I haven’t had boards with any slots before and it’s just showing them as normal holes. 

Diptrace’s export preview and kicads gerber viewer show them just fine so I assume it’s a Gerbv thing but I thought I’d check on the off chance there’s something whacky about the drill file. Anybody know if Gerbv should handle slots?