Answer
Convert breakdown dates to integer and compares serial numbers in a range of days specified by a parameter.

1. Place Measurement Date to columns and select discrete.
2. Place Value to rows.
3. Place one more Value to rows and right click Dual Axis.
4. Right click the right Y axis and click Synchronized Axis.
5. Right click the right Y axis and uncheck Show Header.
6. Open SUM(Value)(2) mark card and change mark type to Circle.
7. Create a parameter with integer type and name it Specify a range of days.
8. Right click the Specify a range of days parameter and click Show Parameter.
9. Create a calculated field and name it INT(Breakdown Date).
INT([Breakdown Date])
10. Create a calculated field and name it N days before breakdown.
WINDOW_SUM(SUM([INT(Breakdown Date)]),0,[Specify a range of days])
11. Create a calculated field and name it N days after breakdown.
WINDOW_SUM(SUM([INT(Breakdown Date)]),-[Specify a range of days],0)
12. Create a calculated field and name it Breakdown flag.
IF [N days after breakdown] > 0 AND [N days before breakdown] > 0
THEN "Breakdown date"
ELSEIF [N days after breakdown] > 0
THEN "N days after breakdown"
ELSEIF [N days before breakdown] > 0
THEN "N days before breakdown"
ELSE "Normal"
END
13. Open SUM(Value)(2) mark card and place Breakdown flag to color.
14. Change the legend colors and parameters as you like.