Cursor at wrong position after inserting BBCode in IE11

When you type a message in IE 11, then press Enter to start a new line and then click on the BBCode button above the textarea, the cursor is inserted in the wrong position: two characters righter than needed. [img][/|(cursor is here)img]
More interesting: if we do it inside an existing BBCode, there is no bug.
The screenshot with the wrong cursor position is attached.

P.S. There's no bug in 3.0.x boards in IE and there's no bug in other browsers.