Observed when loading a document:
Dialog for inputting the password should be implemented in order to be able to decrypt the file content.
It is actually checked and only the appearance is wrong. When the file is saved the checkboxes states are as expected.
This behavior is observed with PdfImportSettings.ReadOnDemand setting only.
While all the pages and components of the control are rendered on the image, the content is completely missing from it. The issue is a regression caused by the migration of the model and its async rendering introduced in R3 2020.
Workaround: Fallback to the old rendering engine:
this.pdfViewer.DefaultImportSettings.UseOldRendering = true;
PdfImportSettings settings = PdfImportSettings.ReadOnDemand; settings.UseOldRendering = true;