I noticed yesterday that my blogroll had disappeared – so I researched and found a fix (adding back the Links widget to the Sidebar) but in the process I noticed a Sidebar entry that is both mysterious and impossible to edit or remove. It is a small box with a number (1365), and a live link to my own blog – it is not listed among the widgets under My Dashboard – I would love to just delete it, but since there is no reference to it, I don’t know how.
I looked at the source code, and it is listed as a “links” widget.
Go to links > links categories and see if 1356 is listed there. If so, then go to settings > writing and choose a default links category. If you had deleted the default “blogroll” links category, and then not set a new default this can happen. Next go back to links > links categories and delete the 1356 category.