If I type Y it shows Y

If I type Y it shows Y in English.

That is because Y is not

That is because Y is not mapped to any character. Anyway, what were you expecting the editor to show?

Most of other software I

Most of other software I explored before used same telugu character which is used for lower case "y".

case changing is allowed now

From now on if a key does not exist in a key map, a case change is tried to find a match. This means, you will get the desired behavior.

You might have to clean your internet files, so that IE gets the updated file (there is no such requirement for Firefox). I am trying to figure out why IE does not request the file from the server by itself.