Pull request type

Please check the type of change your PR introduces:

• Update
• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes

What is the current behavior?

To call PointFromScreen, the visual needs to be connected to a presentation source. Otherwise an InvalidOperationException with the message This Visual is not connected to a PresentationSource is thrown. This is already catched, but we can avoid this by checking whether it's connected. I also refactored the almost unreadable panel fallback into a separate method.