Message text truncated in WiX user actions

Question

I use the Microsoft.Deployment.WindowsInstaller.Session.Message method to display a message to a user with a custom action using the following code:

var record = new Record();

record.FormatString = message;

session.Message(InstallMessage.Info| InstallMessage.User | (InstallMessage)MessageButtons.OK, record);

The message I'm trying to show is:

My product name was successfully set to C: \ Program Files (x86) \ My Company \ My Product Name. Now you should check ServiceHostWindowsService.exe.config and update the configuration for a specific installation, then run My Product Name. You must check the Windows application event log to ensure all services started correctly.

But what is actually displayed:

My product name has been successfully set to ... \. Now you should check the ServiceHostWindowsService.exe.config file and update the configurations for a specific installation, then run My Product Name. You must check the Windows application event log to ensure services have begun ...

Can someone explain why the text is truncated to 254 characters? Is this a known limit? If so, can you point me to the documentation? Is there a way to show a longer message?

Thanks in advance,

Charles.