WebView hosting PDF still can't scroll when using the scrollbars on Catalyst

[PureWeen]

Description

#21883

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• WebView in MAUI project doesn't scroll when has a PDF file loaded (#21346), similarity score: 0.79

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[jsuarezruiz]

The result in Catalyst is that:

• Can scroll with gestures on the trackpad.
• Can scroll with the mouse wheel.
• The scrollbar does not work.

Everything works without using a PDF, including scrolling by dragging the scrollbars.

Some tests have been performed, although we need more time to determine the cause.

• The hierarchy seems correct.

• Verified that the WKWebView's ScrollView accepts interactions, has the correct ContentSize and Bounces enabled.
• LayoutView and the HitTest method (used to manage the InputTransparent property) has not impact here.
• MauiWebViewNavigationDelegate has no impact. No changes in the behavior without using it.
• Verified the ScrollView ContentInset and ScrollIndicatorsInsets. Changing the insets, get the same behavior.
• Removing the custom maui WebView Configuration not affect the scrollbar problem.

[PureWeen]

This is an issue with catalyst itself. @jsuarezruiz tested this with a catalyst platform app and saw the same result.

I can't comment on the complexity of this, but, one alternative might be to use
https://developer.apple.com/documentation/pdfkit/pdfview