How to duplicate (not extend) conditional formatting rule?

  1. Click any cell covered by the original conditional formatting
  2. In the menu, pick format/conditional formatting...; this opens a side panel with all conditional formats that apply to that cell
  3. Click the format you want to duplicate
  4. Do not edit anything yet
  5. Click "Add another rule" on the bottom. This will save any changes you made to your original format ... and open a new clone.
  6. Change the range on the newly created clone.
  7. Repeat 5 and 6 until you enter the last range
  8. Click "Done".