BACKPORT - Placing anchors is not possible in IE7

Select a word, click on the InsertAnchor, add some keyword to it, check html mode and see that nothing changed.

This issue is caused by http://trac.xinha.org/attachment/ticket/1577/, introduced with the 'new' dialogs in xinha.

To reproduce:

in the console:

• add the InsertAnchor plugin to the xinha plugin plugins configuration (Xinha.plugins property)
• add the insert-anchor action to the toolbar (Xinha.config.toolbar)
• save
  in the cms:
• open a document with a rich text field
• select some text and create an anchor
  result:
• nothing changes, either visually or in the html code
  expected:
• an anchor symbol is shown near the selected text
• when viewing in html mode, a <a name=...> tag has been created