Always select all in SSRS cascading parameters

I have 2 parameter lists. 1 is Owner and 1 is unit which is dependent on owner. These are multiselect parameters.

By default select all is chosen for both so right when you enter the report select all is selected for both Owner and Units.

Now when I uncheck select all and check 3 owners it again selects checks all units in the unit list. Now when I select a 4th owner it appears to select all in the unit list but it actually does not select the new unit that was added fr开发者_如何学Goom the newly selected owner. Whats the deal?

Thanks

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What is happening is as follows:
1. When you first come to the report, the cascading parameters are populated with everything checked
2. You uncheck a bunch of owners, it cascades through and deletes the units corresponding the unchecked owners ( note the default selection hasn't changes, just the list of available units)
3. You check owner4, it cascades through and adds the corresponding list of units to the drop down. However, the default selection has already been made, so these items are now not checked.

Basically, you only have one chance to select the defaults, you cannot do it multiple times. Once the defaults are populated, all further selections are user driven.