Combo charts : Hiding dimension value when measure not calculated

[orangebloss]

In my combo chart the measures only calculate if there are any late values (shown in red below) using the format :

if(Sum({<SevenDayTaskCompletionTimeStatus = {"Overdue","Late to Milestone"},TaskName-={TaskName1}>} EstimateHours)/

Sum(EstimateHours)>0,
Sum({<SevenDayTaskCompletionTimeStatus = {"Overdue","Late to Milestone"},TaskName-={TaskName1}>} EstimateHours)/

Sum(EstimateHours))

and substituting the measure to be calculated with the other status (e.g. Complete). I'd like to hide any of the dimension values where the calculation is not performed and leaves a blank space. Currently my dimension is created using the following :

if(ProjectId='556802'and TaskListId<>'2206984' and TaskProjectType='CME',

TaskName1)

I've tried calculating if the count or sum of the SevenDayTaskCompletionTimeStatus >0 and adding that to the dimension but this doesn't work. The data is built using the hierarchy function - TaskName1 is the task displayed on the bottom of the chart and the calculations are done on everything that is not TaskName1 (i.e. everything below it).

Help appreciated!