How to make a column invisible in an ssrs matrix

Question

I have an ssrs matrix , the design of which looks like this :

The sql

Answer 1

I don't know, why it shows blank space, but here is how I handled this problem:

1. Choose "column visibility" property of column "Change"
2. Then I added expression for hiding column: =IIF(Month(Fields!Date.Value)=Parameters!UserSelectedDate.Value,True,False)

And when I select report parameter to 1 and preview the report, it hides Change column for month 1: