WebView bug: Window Maximize does not update size

[Zerq]

So if i do a layout with a webview that supposed to take up any remaining space apart from the other UI elements and i then Maximize the window then the webview component fails to update its size according to the layout.

but if i use the bottom right corner to resize a window it does update according to the layout.

[cagianx]

I'm having a similar bug in my app, this is what my AI was able to figure out and I'm reporting it to you, maybe it can help.

My AI suggested that the resize issue may actually be in Platform.Maui.Linux.Gtk4, specifically in LayoutHandler.

After reading the v0.6.0 sources, this looks like a combination of two problems in src/Platform.Maui.Linux.Gtk4/Handlers/LayoutHandler.cs:

1. ConnectHandler attaches an anonymous window.OnNotify resize handler, but it does not seem to unsubscribe it in DisconnectHandler.
2. That handler calls DoLayout(), which accesses VirtualView; after a page is disconnected, this can lead to:
   InvalidOperationException: VirtualView cannot be null here
3. Even when it does not crash, the resize handler reads window.GetAllocatedWidth() / GetAllocatedHeight() during notify::default-width/default-height, which may still be the previous size at that moment, so layout is recomputed with stale constraints.

This matches what I see:

• sometimes resize crashes
• otherwise the page just does not visually resize correctly

As an app-side workaround, avoiding page destruction (RemovePage) helps prevent the crash, but it does not fully solve the stale resize behavior.

Possible fixes might be:

• store and unsubscribe the window.OnNotify handler in DisconnectHandler
• make DoLayout() safe when the handler is already disconnected
• avoid using GetAllocatedWidth/Height() too early in OnNotify (maybe defer with IdleAdd, or use a size source that already reflects the new dimensions)