dropdown length- allow multiple values

Hi,

The report has two parameters.

Date and clients

The client parameter is a dropdown list which has been set to "Allow Balnk Value".

On selecting the Date, the clients dropdown is populated with clients AND the length of the dropdown control goes as wide as the client names.

Question:

If for the client dropdown list, I set the parameter to "Allow multiple values", then on selecting a Date, the clients list populates BUT it does not go as wide as the clients width. It seems that the width is set to a default width.

HOw can the width of the client dropdown be changed when the setting is set to allow multiple values.

Thanks