Bug report: Dropdown menus close themselves ~1 second after opening, only when a touchscreen digitizer is present and enabled

Bug report: Dropdown menus close themselves ~1 second after opening, only when a touchscreen digitizer is present and enabled
Summary
On a touchscreen-equipped Windows laptop, every top-level menu in Photoshop (File, Edit, Select, etc.) closes itself automatically about one second after being opened — before any item can be clicked. Modal dialogs (e.g. Edit > Preferences) are unaffected and stay open normally. The issue disappears completely and reproducibly when the touchscreen hardware is disabled in Device Manager, and returns when it is re-enabled and the system is rebooted. No other application on the same machine (tested: CorelDRAW, Notepad, File Explorer, Windows Settings) shows this behavior.
Environment
Laptop: HP Spectre x360 Convertible 15-eb1xxx (convertible touchscreen laptop)
OS: Windows 11 (driver stack build 10.0.26100.9711, i.e. 24H2)
Touch digitizer: ELAN2514 (`HID\\VEN\_ELAN\&DEV\_2514\&Col01`), exposed as "HID-compliant touch screen" in Device Manager, using Microsoft's generic in-box HID digitizer driver (no vendor-specific driver installed)
Photoshop version(s) affected: [FILL IN — Help > About Photoshop — reproduced on both the 2024 and 2025 desktop releases]
GPU: [laptop integrated/discrete GPU — Use Graphics Processor tested both ON and OFF, no change]
RAM: 16 GB
Steps to reproduce
Make sure the laptop's built-in touchscreen is enabled (Device Manager > Human Interface Devices > "HID-compliant touch screen" > Enabled).
Open Photoshop.
Click any top-level menu (File, Edit, Select, etc.) with the mouse — do not touch the screen at all.
The menu opens normally, but closes itself on its own within roughly 1 second, before any item can be selected.
Expected result
The menu stays open until an item is clicked or the user dismisses it.
Actual result
The menu closes itself automatically after ~1 second.
Reliable on/off switch found
Device Manager > disable "HID-compliant touch screen" → bug disappears immediately, every time.
Re-enabling the device live (no reboot) → Photoshop continues to work fine for the rest of that session.
Re-enabling the device and rebooting the PC → bug returns.
This indicates the trigger is not "finger touch input" itself (the screen is never touched during reproduction) but simply the presence of an active, enabled touch digitizer in the system at the time Photoshop starts/runs.
Visual evidence
Screen recording shows the Windows "busy" (spinning) cursor flashing at the pointer location roughly once per second while a Photoshop menu is open and the touchscreen is enabled; the menu closes itself in direct correlation with one of these flashes. This looks like a brief UI-thread stall/re-sync tied to pointer/touch input processing, happening at roughly 1 Hz.
Other causes ruled out during troubleshooting (so these don't need to be re-suggested)
Photoshop preferences reset (Ctrl+Alt+Shift at launch, settings file deleted) — no change
Third-party plugins disabled (Shift-launch safe mode) — no change
Preferences > Tools > "Enable Gestures" — already off by default
Preferences > Tools > "Enable Flick Panning" — turned off, no change
Preferences > Technology Previews > "Enable Modern User Interface" — turned off, no change
Preferences > Performance > "Use Graphics Processor" (GPU acceleration) — tested both on and off, no change
Network disconnected — no change
Adobe Desktop Service.exe ended — no change
Reproduces identically on two different Photoshop major versions (2024 and 2025) on the same machine
Wacom Intuos4 tablet driver fully uninstalled (was causing an unrelated, separate system-wide focus-stealing issue in other apps, now fixed) — Photoshop-specific menu bug persisted after this unrelated fix
Windows "Pen Service" (per-user service `PenService\_<id>`) stopped and disabled via `sc.exe` — no change
Synaptics TouchPad Enhancement Service (`SynTPEnhService`) — already disabled, not the cause
`TextInputManagementService` could not be tested directly (protected by a TrustedInstaller-level ACL, cannot be stopped even from an elevated administrator PowerShell session)
Checked for a newer vendor/firmware update for the ELAN2514 touch controller — none available (HP's own diagnostics report "all drivers are up to date" for this exact model/serial)
CorelDRAW, another GPU-accelerated creative app, shows no menu issue at all when run simultaneously on the same machine with the touchscreen enabled — rules out a generic GPU/display-driver explanation
Possible related root cause
This may be the same underlying issue described in the Adobe Community bug thread "Completely broken Hand tool (PS24.5) — Hand tool sticking/sticky, not seeing mouse-up" (bug-reports-711/660423), where an Adobe Community Manager (CJButler) explained that Photoshop does not reliably call `EnableMouseInPointer(false)` at startup, which can leave Photoshop processing Windows Pointer (WM_POINTER) messages instead of legacy mouse messages when a pointer/touch/pen device is present in the system — and separately noted outstanding `PeekMessage` issues when the message queue is busy. A partial fix shipped in Photoshop 25.6 for "the mouse case," but it was noted that "stylus [pointer] cases might still fail." The behavior reported here (menu self-closing, correlated with ~1 Hz UI stalls, present only when a touch digitizer is enabled, absent with no digitizer present) looks consistent with Photoshop's menu modal loop receiving unexpected/duplicate pointer-frame messages from Windows' pointer input pipeline while a touch digitizer is active, even though the screen itself is never touched.
Attachments
Screen recording showing the Windows busy-cursor flash and the menu closing (available on request)