In Dynamics AX 2012, when you open the forms,  you might see some of them open behind the other forms. User may get the impression that the form was never opened.  This happens if the form opened slowly;  a cold start, uniqueness of the data including large number of records or complexity of the form may cause the form to load up slowly.  The form hide behind the other form because of Windows’s ‘ForegroundLockTimeout’.

Doing the following changes to your system could fix this issue.  Since it involves changing a registry key in your system, take necessary precautions.

Create a Restore point before performing the steps below as a precaution.

http://windows.microsoft.com/en-US/windows7/Create-a-restore-point

Steps:

1. Open registry>> Start>>Type regedit>>press enter.

2. Locate the key:

HKEY_CURRENT_USER\Control Panel\Desktop

3. On the right pane right click on the following key and select modify:

4. ForegroundLockTimeout

5. Select Base as decimal and then type 0 (zero) in the value data box and click on Ok.

6. Exit from registry and restart the computer.

REGISTRY EDIT DISCLAIMER:

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756 How to back up and restore the registry in Windows