One of the new feature additions to Terminal Services RemoteApp (TS RemoteApp) in Windows Server® Code Name "Longhorn" Beta 3 is multi-monitor support - the ability for a remote program to be dragged between primary and secondary monitors, to be maximized on any monitor and have it stick correctly to that monitor, etc. In other words, RemoteApp programs work just like local programs do in multi-monitor setups. Here is an FAQ of what TS RemoteApp multi-monitor support constitutes.

1. What kind of multi-monitor configurations are supported?
   
   Just like the requirements for usage of the /span switch in normal remote desktop (described in an earlier blog post here), TS RemoteApp also requires the following specifications for the multi-monitor setup:
• Equal resolution monitors
• Total resolution of all monitors not exceeding 4096 x 2048
• Top-left monitor being the primary
  
  Any other kinds of multi-monitor configurations are not supported with TS RemoteApp. Here are a few examples of multi-monitor setups that are unsupported:
• L-shaped multi-monitor configuration
• Unequal number of monitors on the top and bottom row (if there is a two row multi-monitor setup)
• Center or right monitor being the primary
  
2. What do I need to do in order to enable multi-monitor support in TS RemoteApp?
   
   As the administrator, nothing, as long as the client computers are all in the supported multi-monitor configuration. By default, in Windows Server "Longhorn" Beta 3, the RDP or MSI files that are generated by using the RemoteApp Wizard allow multi-monitor usage of RemoteApp programs because the span monitors:i:1 entry is present in the RDP file.
   
   As the end user, you just need to launch the remote program just like you would do normally.
   
3. Can bad things happen if a TS RemoteApp multi-monitor enabled RDP file is used from a single monitor client computer?
   
   No. The span monitors:i:1 option is ignored when the client is not multi-monitor. Hence, there are no side effects of any kind when using these RemoteApp RDP files from single monitor clients.
   
4. Will RemoteApp programs launched from a Terminal Services Web Access (TS Web Access) portal on a multi-monitor client also have this support?
   
   In Windows Server "Longhorn" Beta 3, RemoteApp programs launched from a TS Web Access portal do not work across multiple client monitors even in the supported configuration described in FAQ #1. This will be addressed in the next interim milestone release of Windows Server "Longhorn".
   
5. How do I turn off TS RemoteApp multi-monitor support for a particular multi-monitor client computer?
• If the administrator has already generated the RDP file(s) by using the RemoteApp Wizard and pushed them on to the client computer, she will have to manually edit the RDP file(s) on that client computer to set the span monitors field to 0, i.e. it should read span monitors:i:0.
• If the administrator has already generated the RDP file(s) by using the RemoteApp Wizard and the user is launching the RemoteApp program through a TS Web Access portal, there is no way for her to turn this functionality off for a particular client computer.
• If the administrator is in the process of generating the RDP or MSI file(s) by using the RemoteApp Wizard and decides that for a particular client computer she does not want to provide TS RemoteApp multi-monitor support, she can use the "Custom RDP Settings" tab in the TS RemoteApp Manager tool for this. All she needs to do is to put "span monitors:i:0" in the text field on that tab and the generated RDP or MSI file(s) will have the functionality turned off. Then, she needs to push this particular set of RDP or MSI file(s) to the target client computer.
  
6. What client operating system do I need to test this feature?
   
   As of now (7 May 2007), this feature can be tested only with Windows Server "Longhorn" Beta 3 being the client operating system, i.e. both the client computer and the remote server must be running Windows Server "Longhorn" Beta 3.