The error code 0x000005A1 translates to ERROR_HWNDS_HAVE_DIFF_PARENT. This error occurs in Windows programs when you attempt to use certain window management functions with windows that have different parent windows.

Understanding Window Hierarchy:

• Windows applications are organized in a hierarchical parent-child relationship.
• A parent window is a container window that can have child windows within its client area.
• Certain window management functions operate specifically on child windows within the same parent window.

Causes of ERROR_HWNDS_HAVE_DIFF_PARENT:

• Incorrect Window Handles: The most common cause is trying to use a function like SetWindowPos or BringWindowToTop on two window handles that belong to different parent windows. These functions typically expect sibling child windows under the same parent.

• Code Errors: Mistakes in how you’re managing window handles or understanding window relationships can lead to this error.

Troubleshooting Steps:

1. Verify Window Relationships: Double-check that the window handles you’re using in your function call are indeed child windows of the same parent window. You might need to examine how you obtain or manage these handles in your code.

2. Target Sibling Windows: Ensure you’re only using these functions with window handles that represent sibling child windows within the same parent window hierarchy.

3. Debug Window Handles: Use debugging tools to inspect the window handles you’re passing to the function. Verify their parent-child relationships to identify potential mismatches.

4. Review Function Documentation: Refer to the documentation for the specific window management function you’re using (e.g., SetWindowPos, BringWindowToTop). The documentation might specify requirements related to window hierarchy and parent-child relationships.

5. Alternative Approaches: Consider alternative approaches if you need to manage windows that aren’t siblings. This might involve using functions designed to work with non-child windows (like SetForegroundWindow) or iterating through the child window list of a parent window to identify and target specific child windows.

Additional Tips:

• Use meaningful variable names to differentiate between window handles, especially when working with multiple windows.
• Consider using higher-level UI libraries or frameworks (if available) that might provide abstractions for window management tasks, potentially simplifying handling of window relationships.

By following these steps and understanding the reasons behind the ERROR_HWNDS_HAVE_DIFF_PARENT error, you should be able to identify the issue with your window handles and fix your code to use window management functions appropriately within the correct parent-child window hierarchy.