Strange table bug adds table cells

Strange table bug adds table cells

When you select all cells of a table and then click on one of the tables, in 50 % of the cases a table cell gets added before all other cells in the table. That means the cells of the first row are shifted right and a new column is added to the right (see attachments). This is very annoying.

Any idea? (Firefox 2.0.0.12)

Best regards,
Patrik