The compass elements are not on the proper places when the docking is on the second monitor. To reproduce this the DPI of the monitors should be different for example 125% (main) and 150% (secondary). Also, to reproduce this you will need to enable the DPI awareness of the application by setting the dpiAware and dpiAwareness settings in the app.manifest file.
Implement UI for hiding sheet. The sheets can be visible, hidden, or very hidden (could be made visible only from the API). Note: This is already supported on model level (in RadSpreadProcessing).
The control should be customizable so you can place also a content different than an image as in the WPF native splash screen support (https://docs.microsoft.com/en-us/dotnet/framework/wpf/app-development/how-to-add-a-splash-screen-to-a-wpf-application).
The ImagesDeflaterCompressionLevel and ContentsDeflaterCompressionLevel in the PdfFormatProvider's export settings have 0 for default value instead of -1. Workaround: Change the settings's properties to -1 explicitly.