I am using Sumatra PDF V-3.2 in Windows 10.
It happens frequently that if I have some files open (even just one) in Sumatra PDF, and I click on another PDF file in my file explorer (the standard double click), it doesn’t open, nothing happens. In order to open an additional file, I have to open file explorer from inside Sumatra app (using CTRL+O, which opens the file explorer) and select the files to open.
This doesn’t happen always, but now and then.
This issue wasn’t there before in earlier versions I used. I have been using this software since last 5 years, it worked pretty well before.
Sumatra is my only/default external PDF reader in my PC.