An application, that we recently converted from PB12.5.2 to PB2017, opens documents thus
ll_rc = ShellExecuteW ( Handle( gw_mdi ), "open", ls_path , ls_null, ls_null, 1 ) where ls_path is the full path & filename.
If the file is a PDF and the default PDF viewer is Acrobat Reader DC then the file is opened in Acrobat, but it is not possible to view any more PDF documents by double clicking in the file explorer - each time a new Acrobat session starts in background mode and nothing is displayed. This works in the old version of the software. We're rather concerned if there is an issue with PDF processing with PB2017, because we do this a lot in our main application, In order to continue using acrobat, it is necessary to kill all open Acrobat sessions.
The director who is getting this problem is using 64 bit W8.1 and both the compiled application and Acrobat are 32 bit. If you have, say, Edge or another PDF viewer specified as the default viewer then there is no problem. Acrobat shows no problems when not called from our application. I cannot replicate this problem on my 64 bit Windows 10 machine.