[Problem/Bug]: WebView2 Runtime 152.0.4191.66+ stops responding to mouse and keyboard input in Composition Mode #5713

What happened?

We are seeing a severe input regression with WebView2 Runtime 152.0.4191.66 and later when using Composition Mode.

After performing a specific drag operation, the WebView can enter a state where it remains visually and functionally alive in some respects, but mouse and keyboard input are no longer processed.

The issue appears to be intermittent and machine-dependent. On affected machines, we can reproduce it very frequently, typically after 3–4 attempts.

Steps to Reproduce

• Launch our application with WebView2 in Composition Mode.
• Open a web page in the WebView.
• Select some text on the page.
• While the text selection is active, start dragging the selection.
• Drag the mouse outside the application window.
• Repeat the operation several times.

On some machines, after approximately 3–4 repetitions, the WebView enters the problematic state.

Actual Behavior

Once the issue occurs:

Mouse click events are no longer processed.
Mouse hover states no longer work.
Buttons and other interactive elements do not respond to mouse clicks.
Keyboard input is no longer processed by the WebView.
However, the WebView itself is still alive.

The following operations continue to work:

Page refresh
Window resize
Mouse wheel scrolling

This makes the issue particularly difficult to detect because the WebView does not appear to have crashed or become completely unresponsive.

In other words, the WebView appears to remain operational, but its mouse click/hover and keyboard input paths become unresponsive.

Expected Behavior

Mouse and keyboard input should continue to work normally after dragging a text selection outside the application window.

The WebView should not enter a state where only some input and browser operations continue to work while mouse click, hover, and keyboard input stop responding.

Frequency

The issue is intermittent and appears to be machine-dependent.

On affected machines, the issue can usually be reproduced within 3–4 drag operations.

Additional Observations

The issue appears to be specific to the WebView2 Composition Mode input path.

The WebView does not appear to crash:

The page can still be refreshed.
The WebView can still be resized.
Mouse wheel input continues to work.
The rendered content remains functional enough to perform browser operations.

However, normal interactive input is lost:

Mouse click → Not processed
Mouse hover → Not processed
Keyboard input → Not processed
Mouse wheel → Still works
Resize → Still works
Refresh → Still works

We are also investigating the interaction between this issue and the recent Chromium/WebView2 changes related to app-region: drag / non-client hit testing in Runtime 152.

Regression

This behavior was not observed with previous WebView2 Runtime versions in our testing.

The regression appears to start with:

152.0.4191.66 and later

Impact

This is a severe usability issue for applications using WebView2 Composition Mode.

Once the WebView enters this state, the user cannot interact with the page normally. In our application, the only reliable recovery currently appears to be recreating the WebView2 instance.

Questions

Could the WebView2 team investigate whether there is a known issue in Runtime 152.0.4191.66+ related to:

Composition Mode input handling
Dragging text selections outside the application window
Mouse capture/release
Pointer/mouse event routing
Keyboard input routing
Non-client hit testing / app-region: drag
GetNonClientRegionAtPoint
Composition Controller input state

Is there any supported API that can be used to determine whether the Composition Controller's mouse/keyboard input pipeline has entered an invalid state and recover it without destroying and recreating the WebView?

Thank you.

Importance

Blocking. My app's basic functions are not working due to this issue.

Runtime Channel

Stable release (WebView2 Runtime)

Runtime Version

152.0.4191.66+

SDK Version

4255.0

Framework

Win32

Operating System

Windows 11

OS Version

No response

Repro steps

Steps to Reproduce

1. Launch our application with WebView2 in Composition Mode.
2. Open a web page in the WebView.
3. Select some text on the page.
4. While the text selection is active, start dragging the selection.
5. Drag the mouse outside the application window.
6. Repeat the operation several times.

On some machines, after approximately 3–4 repetitions, the WebView enters the problematic state.

Repros in Edge Browser

No, issue does not reproduce in the corresponding Edge version

Regression

Regression in newer Runtime

Last working version (if regression)

No response