- Open a page in 'edit' mode
- Click in the summary field
- Click in the "Link" button of the (enhanced) toolbar
- Fill the fields "Target page or URL:" and "Text to display:" with some random text (e.g. "foo" and "bar")
- Click on "Insert link"
- The text [[foo|bar]] should be added to the summary field (i.e. the one with focus when the button is clicked)
- The text [[foo|bar]] will be added to the edit box
The same happens with other buttons (although they are not that useful for a summary) but works fine with the old toolbar (which inserts [[Link title]] in the summary).