Horizontal splitting and combining
Splitting and combining cells
You can split a cell into two horizontally by adding a partition, or remove it to combine two cells into one. Use the Split table cell and Combine table cells commands in Main menu / Table or corresponding Table toolbar toolbuttons.
Here is a table, originally 3 rows and 2 columns, which has had split and combine operations carried out on the second and third rows respectively.
Splitting columns
To split a column of blank cells into two: highlight the whole column then click the Split table cell toolbutton.