Dragoons cannot charge any non-light troops (including fragmented ones) in rough and difficult terrains either, right ?

In other words, Dragoons can only charge :
- fragmented non-light infantry or cavalry (?) in open terrain,
- any artillery (fragmented, disrupted or steady) in open terrain,
- light troops anywhere (rough, difficult open or non-open terrain),
(edit)
- any non-light infantry (fragmented, disrupted or steady) in difficult, rough or non-open terrain (à leurs risques et périls) ?