On SE D750i file browsing starts to misfunction after direction keys were used ie. selecting anything else than C: results in next screen devoid of selection highlight (there is no way to choose anything from the displayed list and go further).
Fixed in upcoming v1.2.0
This error (disappeared selection) also was on K750.
K750i, D750i and W800i is the same hardware with slightly different software.
Please test new version (1.2.0)
New version works fine on these phones.