Sql-server – limit to how many credentials SSMS can remember

Using SQL Server Management Studio that came with SQL Server 2008 R2, I make connections to the same server using a number of different sets of SQL Server Authentication credentials. On my development machine, I use the Remember password checkbox extensively to avoid having to look up the password each time.

When I choose a Login which I have previously connected with (using Remember password), the Password entry field gets populated with asterisks, and clicking Connect allows me in – most of the time. But sometimes, with no pattern that I can discern, on choosing a previously-used Login, the Password field will prepopulate with asterisks, but clicking Connect tells me the login fails. I enter the password, click Connect, and get in, and then typically the next time I use the same login it will work.

My suspicion is that there is a maximum number of credentials that SSMS is prepared to remember, and only the most-recently-used n credentials are actually remembered, but I can't find any mention of such behaviour in the documentation.

Is there a known limit on how many credentials SSMS will remember?