IE: toolbar buttons don't respect cursor location.

[Jakub Ś]

This bug is related to #7796 where @fredck mentioned how browser sees element boundaries ​comment:4 and that current cursor location should be reflected by what the user sees on a toolbar ​comment:8.

To reproduce:

1. Switch to source and paste in the following code

   <center>
   	<p>
   		<b>HELLO World</b><br />
   		<br />
   		&nbsp;</p>
   </center>
   

2. Switch to source
3. Click to the right of the "Hello World" but on the same height of this line - so that the cursor appear right after "Hello World^"
4. See that in IE8 and IE9 toolbar button "Bold" is IN MOST CASES not turned on
5. Start typing or paste some text using CRTL+V or paste button (right-click to activate context menu turns on the bold button so pasting from context menu works)

Result: text is written/pasted in bold.

Issue has been reproducible from CKEditor 3.0 in IE8 and IE9.