Hiding All level in Dimensional view

[vemulap1]

Hi,

I have dimensional view called Business Type,  it has 3 levels.  When i model it in FM, the structure is as follows
Business Type (All)
Level1
Level2
Level3

I need to hide Business Type (All), so that when i open from Analysis studio, it goes stright to level1.
When I use ishidden = true for the (All),  I get an error Not all key items of level 'Business Type' can be applied.

Have any one faced this issue.

Thanks