[Bug 60178] New: indowless transparent NPAPI plugin content is cleared to blank and not repainted when the host window is deactivated or a popup appears; only physically moving the window restores it. Works correctly on Windows.

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=60178

            Bug ID: 60178
           Summary: indowless transparent NPAPI plugin content is cleared
                    to blank and not repainted when the host window is
                    deactivated or a popup appears; only physically moving
                    the window restores it. Works correctly on Windows.
           Product: Wine
           Version: unspecified
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: winex11.drv
          Assignee: [e-mail]
          Reporter: [e-mail]
  Target Milestone: ---
      Distribution: ---

Wine 11.15 (Staging), x86_64, wow64
- Ubuntu 26.04 LTS, GNOME (Mutter / X11 session), DPI 120
- Host application: Chanjet T+ Browser (Chromium ~60 based, 2018 build), 32-bit
PE
- Run flags: `--enable-npapi --disable-gpu --disable-gpu-compositing
--disable-direct-composition --disable-accelerated-2d-canvas
--disable-direct-write --force-color-profile=srgb`

## The plugin
- NPAPI plugin `npBillOne.dll`, **windowless + transparent** mode
  (implements `IOleInPlaceSiteWindowless`; renders via `CreateDIBSection` +
`AlphaBlend`)
- The plugin draws its print-preview content directly into the browser page
area
  (there is no separate top-level HWND for the preview document).

## Steps to reproduce
1. Launch the browser and open a document, then open the plugin's print preview
   (the preview content renders correctly at first).
2. Do ONE of the following:
   - move the mouse pointer out of the browser window (window loses focus), or
   - open the plugin's drop-down menu (printer / paper list).
3. Observe the preview content area.

## Actual result
The plugin-drawn preview area is cleared to **white/blank** and is **never
repainted**,
even though the window is still visible. The rest of the page (normal Chromium
content)
renders fine — only the windowless plugin region is affected.

## Expected result
The plugin region should keep its content (as on Windows) or be repainted
automatically.

## Workaround (the only thing that restores the content)
**Physically drag/move the window.** A real window move makes Chromium repaint
the
windowless plugin region and the content reappears. Neither of the following
reproduces
the fix:

## What was tested (all FAILED to restore the content)
1. `RedrawWindow(hwnd, NULL, 0, RDW_INVALIDATE | RDW_ALLCHILDREN)`
   → repaints only ~1/5 (left strip) of the plugin region.
2. `SetWindowPos(..., SWP_FRAMECHANGED | SWP_NOMOVE | SWP_NOSIZE)` → no effect.
3. `SetWindowPos` with a real 1px move → no effect (window does not actually
relocate).
4. `_NET_MOVERESIZE_WINDOW` client message (multiple gravity values) → WM
refuses to move the window.
5. XTest synthetic `MotionNotify` over the region → no effect.
6. XTest synthetic window-drag gesture (title-bar drag / Super+drag) → no
effect
   (Mutter ignores synthetic input for window-move gestures).

## Diagnostic evidence collected
- The host window's surface clip region stays the full window at all times
  (`update_surface_region` region == full client rect). No surface replacement,
  no `client_surface`/GL activity — the app is pure GDI.
- Sending `XClearArea(exposures=True)` on the window does not restore it
  (Expose → repaint keeps the already-white content), proving Wine's surface is
  intact; the blank region is because the windowless plugin is simply not asked
to redraw.
- A genuine interactive window move (which generates `WM_WINDOWPOSCHANGED` +
move/expose
  sequence through the WM) is the only thing that makes Chromium re-invoke the
plugin paint.

## Analysis / hypothesis
On deactivation (`WM_ACTIVATEAPP` false / `WM_KILLFOCUS`) or when a popup is
shown,
the windowless plugin region is invalidated, but Wine does not deliver the
repaint in a
way that makes the (Chromium 60) host re-invoke the plugin's paint callback. On
Windows the
same sequence repaints correctly. The discrepancy appears to be in how Wine
forwards
invalidation/paint for the windowless-plugin region during activation change /
popup handling.

## Additional notes
- Actual printing (via Spooler + XPS virtual printer) works; only the on-screen
preview is affected.
- NPAPI is deprecated, but Wine still advertises windowless NPAPI support,
hence the report.

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[Bug 60178] Windowless transparent NPAPI plugin content is cleared to blank and not repainted when the host window is deactivated or a popup appears; only physically moving the window restores it

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=60178

Austin English <[e-mail]> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|indowless transparent NPAPI |Windowless transparent
                   |plugin content is cleared   |NPAPI plugin content is
                   |to blank and not repainted  |cleared to blank and not
                   |when the host window is     |repainted when the host
                   |deactivated or a popup      |window is deactivated or a
                   |appears; only physically    |popup appears; only
                   |moving the window restores  |physically moving the
                   |it. Works correctly on      |window restores it
                   |Windows.                    |

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[Bug 60178] Windowless transparent NPAPI plugin content is cleared to blank and not repainted when the host window is deactivated or a popup appears; only physically moving the window restores it

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=60178

Ken Sharp <[e-mail]> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Version|unspecified                 |11.15

--- Comment #1 from Ken Sharp <[e-mail]> ---
Now try with vanilla Wine.

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