Setting DefaultBackgroundColor on WebView2 affects Web add-ins

[tiagoabreu]

Description
We have a VSTO add-in that uses WebView2. Setting the DefaultBackgroundColor on the WebView affects any web add-in loaded later.

Version
SDK: 1.0.1293.44
Runtime: 105.0.1343.53
Framework: WinForms
OS: Win10 21H2

Repro Steps

1. Install Web add-in that opens a simple page
2. Run Sample add-in that sets a background color for the WebView (in this case, red)
3. Verify the task pane created from the Sample add-in is open
4. Open the Web add-in.
5. Notice how the background is also red.

Notice how in the previous image the web add-in is red. That color was set by the VSTO add-in.

We provide a sample vsto add-in for Excel and a sample web-addin where the issue is easily verifiable.
The color is set in class Browser.designer.cs, line 38.

ExcelWebAddIn1Manifest.zip
SampleAddinWithWebView2.zip

[victorthoang]

@tiagoabreu thank you for your investigation,

@oggy22 will help to investigate this, and we will add it to our backlog to correct.

[tiagoabreu]

@oggy22 Is there any update on this issue?

[victorhuangwq]

@tiagoabreu are you still facing this issue?

[tiagoabreu]

No, because we applied a workaround where we created a background color for the web add-in, so if it happens it would not be noticeable.

But with the repro steps you should be able to figure out if the issue is still there.