Hi,
The sudden closing of the connection dialog is due to an uncaught exception, probably due to something bad with Connector/NET installation
Some suggestions:
1) Can you check your machine.config? It must have a registered MySql Connector/NET provider, something like this (version may differ):
<system.data>
<DbProviderFactories>
<add name="Microsoft SQL Server Compact Data Provider 4.0" invariant="System.Data.SqlServerCe.4.0" description=".NET Framework Data Provider for Microsoft SQL Server Compact" type="System.Data.SqlServerCe.SqlCeProviderFactory, System.Data.SqlServerCe, Version=4.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" />
.
.
.
<add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data, Version=6.6.5.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" />
</DbProviderFactories>
</system.data>
2) You can try installing Connector/NET 6.6.5 (which is has same compatibility than 6.5.4 and is a superset of functionality) or 6.7.4 (which is also production ready, however, this no longer has the Visual Studio Integration, which is now availble through MySql Installer)
3) Debug the prb to find the real exception (this will give me more details on what's wrong):
3a) Open two Visual Studio instances.
3b) Attach VS1 to debug VS2 (menu Debug -> Attach)
3c) In the VS1 (Debugger instance), press Ctrl+Alt+E and check the box for CLR exceptions thrown.
3d) In the debugged instance, VS2, open the connection dialog and reproduce the error.
3e) You will see the VS2 (debugged instance) freezes temporarily, and VS1 (debugger) stops at the point of the error, even if you don't have the Connector/NET source code, it should still give the stack trace (paste here) and the details on the exception thrown.
Thanks.