Fix: Fixed issue with focusing file list using touch

[yaira2]

Resolved / Related Issues

• Were these changes approved in an issue or discussion with the project maintainers? In order to prevent extra work, feature requests and changes to the codebase must be approved before the pull request will be reviewed. This prevents extra work for the contributors and maintainers.
  Closes Bug: Tapping blank space (via touch screen) doesn't clear selected item #15051...

Validation
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• Did you build the app and test your changes?
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• Did you remove any strings from the en-us resource file?
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• Are there any other steps that were used to validate these changes?
  1. Select items
  2. Tapped empty space using touch screen
  3. Confirmed selection is cleared
  4. Confirmed long touch and hold still opens right click menu
  5. Confirmed clicking with mouse clears selection
  6. Confirmed right clicking with mouse clears selection

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[hishitetsu]

Sometimes it works, but sometimes not.
Also, flicking also deselects the items. It should only be done when tapped.

[yaira2]

@hishitetsu instead of handling this from the selection rectangle, would it be more reliable to register a separate tap event for the blank space in each layout?

[hishitetsu]

Yes, I think it is not a good idea to handle this with PointerPressed events.