selected text in message editor can not be replaced

There is a problem when composing email.

In “New Message” window, I select a word,
then try to type over, it will not clear the selected text
and I can not type anything at all.
“Backspace” or “Delete” works, but this time cursor is lost,
I can not continue to type, if I do not click the editor
by mouse.
It is the same for both text and html formats.

Surprisingly, if I select the word then select (activate) another
window, then select the “New Message” window again,
it is possible to type over (just once).

Unfortunately, one more problem in message editor:
When I copy a text with spaces at the start of lines,
and paste it in the editor, these spaces are lost.
All text goes left aligned.
Spaces between words are also lost which breaks all
formatting.

And also, if the text is copied and pasted from another place to the message window, all the carriage returns are lost. Message becomes a big one paragraph.
If there is something listed in lines, they all join in the same line.

I forwarded a message and all carriage returns are lost.
The forwarded message was like a garbage of words.

I opened it by clicking ‘Forward’ button again.
Pressed ‘Enter’ where there should be a new line.The format was correct before sending.
After sending, the message in the ‘Sent items’ was again garbage.

I copied it to a new message, it was again garbage in the sent items.

I corrected it again and sent it to my other mailbox. The received mail was in correct format. That means it is corrupted after sending.

(I have the version 4.0.14247.0)

This is resolved in our internal version which will be released in a few weeks,