I fixed the crashes problems!
Here's what I found out:
- if I open an alert box in the main page (where you can find the splash image), it doesn't crash!
-i f I open an alert box ONLY while reading or managing bookmarks, it crashes.
It seems that the Kindle doesn't give permissions to open pop-ups (or can't manage them) from a page that's isn't the index.html!
But, opening an alert box in index.html make the rest of alert boxes work...
So that, wait till tomorrow and I'll release the new portrait version with this workaround (welcome popup!
)