Taskbar Auto-Hide Hover Trigger Buried by Maximized Windows (Z-Order/Focus Bug)

Question

I am reporting a persistent and reproducible bug where the Taskbar auto-hide "trigger zone" is covered by maximized windows. This issue started after a recent Windows update and has survived a Tier-1 Microsoft Remote Support session.

The Symptoms:

• Auto-hide fails 100% of the time when any app is maximized. Hovering at the bottom does nothing.
• Auto-hide works perfectly when windows are windowed (not maximized).
• Temporary Reset: Killing explorer.exe via PowerShell fixes the issue for exactly one hover. As soon as a maximized window is clicked (regaining focus), the taskbar is "buried" again and will not pop up.
• The "Rescue" works: Pressing the Windows Key brings the taskbar up instantly, confirming the process is not frozen—only the mouse-hover detection is blocked.

Hardware & OS Context:

• Mouse: Logitech MX Master 3S (Issue persists even when all logioptionsplus processes are killed).
• OS Build: Win 11 Pro - 25H2 26220.8138
• Display: Current Settings; 3440x1440p @ 59.97Hz - Alienware QD OLED 34in - AW4323DW

Troubleshooting Already Exhausted:

• Microsoft Remote Support Session: A technician remoted in and was unable to resolve the issue using standard UI toggles.
• Restarted Windows Explorer and cleared StuckRects3 registry cache.
• Toggled all "Taskbar Behavior" settings (Alignment, Badges, etc.).
• Performed full SFC /scannow and DISM /RestoreHealth.
• Disabled all overlays (NVIDIA, Discord, Steam) and Transparency effects.

This appears to be a core shell conflict where maximized windows are incorrectly claiming exclusive focus, masking the 1-pixel hover boundary. Is there a known registry override for the Desktop Window Manager (DWM) or a specific MPO (Multiplane Overlay) conflict that addresses this?

Answer 1

No, because it doesn't resolve the issue. It's a lazy band-aid fix.

Answer 2

Hi HarryPotter219,

Thank you for taking the time to share these detailed observations.

Based on the information provided, the taskbar itself remains functional, but the mouse hover trigger at the screen edge does not activate as expected.

At this time, there is no supported registry or Desktop Window Manager (DWM) configuration that changes this behavior. The issue is not related to mouse hardware, third‑party utilities, or system file integrity, and standard recovery steps may only provide temporary relief.

In the meantime, here are some available workarounds that you can try:

• Keyboard access: Press the Windows key to immediately reveal the taskbar.
• Explorer refresh (temporary):
  • Open Task Manager
  • Restart Windows Explorer
• Windowed mode: Keep applications slightly windowed instead of fully maximized to allow the taskbar to appear on hover.

I appreciate your thorough troubleshooting and patience. Additionally, you can submit feedback through the Feedback Hub App (press Windows +F), including your Windows build number and a short screen recording. This helps ensure the behavior is reviewed and addressed in future updates.

Let me know if you need further assistance, feel free to ask me by clicking "Add Comment" or "Add Answer" if you cannot add comment so your response will be visible. Thanks for your effort.

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Answer 3

There is no documented registry override for DWM or MPO in the provided material, and no specific fix for an auto‑hide taskbar hover zone being covered by maximized windows on Windows 11 25H2.

The only directly related behavior in the context is an older issue where topmost or taskbar windows are not correctly kept on top or do not respond as expected when covered by other windows. In those cases, Microsoft confirmed it as a product issue and addressed it via updates, not via registry tweaks or DWM/MPO configuration. For example:

• A known issue where topmost windows are not always in the topmost position in Windows 7/Windows Server 2008 R2 was confirmed as a product bug and resolved through an update, with no registry‑based workaround documented.
• A taskbar interaction issue where clicking icons did not switch programs when the taskbar was covered was resolved by changing the taskbar’s “Always on top” behavior, not by DWM/MPO settings.

Given the parallels (z‑order/topmost behavior and taskbar being obscured), this type of problem is treated as a shell/Explorer bug that is fixed by an OS update rather than by supported registry changes to DWM or MPO.

From the available information, the supported path is:

1. Treat this as a product bug in the shell/topmost handling.
2. Ensure the system is fully updated and monitor for a servicing update that addresses taskbar/topmost behavior.
3. Submit detailed repro steps and diagnostics via Feedback Hub (WIN+F) so it can be tracked and linked to similar reports.

No supported registry or DWM/MPO override is documented in the provided context for this scenario.

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References:

• Topmost windows are not always in the topmost position in Windows 7 or in Windows Server 2008 R2
• Clicking Icon on Taskbar Does Not Switch to Program
• How do I move my taskbar to the side of my screen? - Microsoft Q&A