We are seeing the MDX Designer take a long time to open and to select filters.  Running a Query is fast, but selecting filters from dimension members that only have 2 to 10 members can take up to a minute to display and the same is true when dragging the member into the Filter pane.  Executing the query is not an issue and the returned results even 1000's of rows is fairly quick.&n

Hi rayishome,

According to your description, when you using multiple parameters in Filter in MDX Query Designer, it takes long time to execute the query. Right?

In this scenario, I want to know the version of SSRS you are using. It has reported similar issue in SSRS 2008, and this issue has been released in both SQL 2008 SP1 and SQL 2008 R2. Please refer to link below:

SSRS BIDS Query Designer very slow when using multiple parameters

Also please refer to a blog below:

Speeding up the Query Parameters Dialog in the SSRS Query Designer

Best Regards,