How can I ensure that the entries in the subtable extend downward without disrupting the layout of the regular fields below the subtable?

If you have designed one or more subtables in the middle of the form, and the maximum width of the subtable is smaller than the maximum width of the regular fields below it, the subtable entries will extend downward as it continues to grow, causing the layout below it to be disrupted.

Normal Layout Example:

Disrupted Layout Example:

To resolve this issue, you can add a blank description field right below the subtable and set the merged cell for this description field to the maximum width of the form's design. For example, if the subtable's width is from column A to E, then the merged cell for this blank description field can be set from column A to H (assuming column H reaches the maximum width of the form).

After adding this blank description field, when adding more subtable entries, the layout will extend downward based on the maximum width of this blank description field, avoiding any layout disruptions.