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.