Fixes #2122. Weird visual artifacts on clearing.

[BDisp]

Fixes #2122 - All view size must be cleared.

Pull Request checklist:

• I've named my PR in the form of "Fixes #issue. Terse description."
• My code follows the style guidelines of Terminal.Gui - if you use Visual Studio, hit CTRL-K-D to automatically reformat your files before committing.
• My code follows the Terminal.Gui library design guidelines
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• I conducted basic QA to assure all features are working

[tig]

I pulled this PR down locally and ran it.

The flickering bar is still there. Was this intended to fix that?

[BDisp]

Yes I've got that now. I also check Character Map scenario is blank. The fix corrupt other situations. We have to see the best solution for this.

[BDisp]

@tig what is causing the flickering is the horizontalRuler label of the Scrolling scenario. If you set the Height = 1 the flickering issue stops. This issue only happens with the WindowsDriver. But I don't know why.

[tig]

I merged this PR down locally and I see this issue in the Class Explorer scenario as well.

[BDisp]

@tig can you confirm if that happens with the others drivers? Mine is working well with WindowsDriver on Windows Terminal.

[tig]

Just tested with -usc and I get the same issue.

Can you please fix the merge conflicts in this PR so I can pull it down again and double check again?

[BDisp]

Just tested with -usc and I get the same issue.

Can you please fix the merge conflicts in this PR so I can pull it down again and double check again?

Done @tig. I hadn't realized the conflicts. Thanks.