In Google Sheets on a computer, select the affected cell and open Data → Data validation. Check whether a dropdown rule applies to that cell. If the rule is there but the arrow or chip is missing, open Advanced options and change the display style from Plain text to Arrow or Chip.
01Compare the missing dropdown with one that works
Section linkOpen Data validation for a working cell in the same column and compare the rule’s applied range. For example, if the rule covers B2:B10 and your new entry is in B11, extend the range to B2:B11. If the cell should have its own list, select it and use Add rule, then choose Dropdown or Dropdown from a range.
02Show the arrow without changing the list
Section linkOpen the existing rule and check Advanced options → Display style. Choose Arrow for a visible arrow or Chip for a chip in the cell. Keep the original criteria and click Done. If the sheet uses multiple selections, keep Chip. On mobile, Sheets does not currently let you pick several options even when the rule allows it.
03If the list opens but a choice is missing
Section linkFor a Dropdown rule, check the items under Criteria. For Dropdown from a range, open the source cells and check that the missing choice is inside the referenced range. A new choice added below that range needs the reference extended. After saving, reopen the dropdown in the original cell to confirm the choice appears.
04If you cannot change the rule
Section linkA viewer or commenter cannot edit the sheet. If you can edit other cells but this range is protected, ask the person who manages the sheet to check the rule or adjust access. Give them the sheet tab and the cell address so they can check the right rule.