Text cursor looks strange

The text cursor looks strange. See this screenshot:

What keyboard language do you use? It is a standard cursor for some specific language.

The languages and keyboard mappings that I have tested this with are as shown in the following image. I’m using Windows 8 64-bit.

Also, the text cursor is rendered correctly when the keyboard focus is in the “To” or “Subject” text boxes.

Does the cursor look the same in Internet Explorer?

No; in Internet Explorer, it uses the system standard text cursor.