Under normal conditions, the Table Format dialog box will, when the
aligment is "from left", cap requested changes to the table width to
the width between the margins.  This makes it difficult to create a
table which extends beyond the margins.

Here are the steps to reproduce the problem:

- Select File -> New -> Text Document

- Select Format -> Page
- On the Page tab, for Format select A4
- Click OK

- Select Insert -> Table
- For Columns enter 1
- For Rows enter 1
- Click OK

- Select Format -> Table
- On the Table tab, for Alignment select From left
* The Width field is enabled and shows 17.00cm
- For Width, enter 19, then press Tab

* The Width field shows 17.00cm and the Right field shows -2.00cm

I expected Width field to show 19.00cm, as requested.  Note that the
A4 page width is 21cm and the default left and right margins are 2cm,
so the width between margins is 17cm.

The following steps work around the problem and set the table width to
19cm and the Left field to -1cm:

- For Left, enter -2.01
- For Width, enter 19

* The Width field shows 19.00cm

- For Left, enter -1

- Click OK

* The table has a width of 19cm and it's left edge is 1cm to the left
  of the left margin