Margin release indicators on the ruler are missing due to unknown cause.
Cause:
Unknown; however, the problem ONLY occurs when table cells are merged.
Solution:
Remerge the cells and the margin release indicators will display.
1) Select the table cells.
2) Select the 'Table' menu and select 'Split Cells'. (The cell splits into individual cells.)
3) Select the 'Table' menu and select 'Merge Cells'. (The margin release indicators and tab stops reappear in on the ruler.)
