Google rolled out a security patch with version 77.0.3865.75 that prevents the print dialog opening automatically in case a PDF document is embedded in an IFRAME.
This change is documented in this official Google Git commit. In our online document editor, which is part of TX Text Control .NET Server for ASP.NET, we use this functionality to enable client-side printing which was broken with the recent Google Chrome release.
We were able to implement a fix for this issue and published a new NuGet package that is available immediately:
If you are using MVC, we recommend to update the NuGet package and to roll out this new version.
For WebForms, we will provide a fix within the next service pack. In the meanwhile, please contact our technical support to get a workaround solution.