I am trying to copy the Previous Cell if the current cell is Null.To achieve this i am using this formula
IIF(ISNULL( SUM([Running Total])), PREVIOUS_VALUE(SUM([Running Total])) ,SUM([Running Total]))
and this is working fine .
But i am facing a challenge when i apply filter on date column . When i try to apply filter on date column values are getting changed to NULL .
First Text column is not picking its previous column value if it is NULL.
In the first half of image no filter is applied so the values for its corresponding months are Nov,2016 -->-4633 Dec,2016-->-4633 Jan,2017 -->-4633
But after applying the filter for the month Jan,2017, its corresponding cell has become empty but i want the value as -4633 as it is even after applying the filter.