In version 188.8.131.52 and a couple of versions prior to that, Edge Dev hangs trying to open most PDF files when those files are double-clicked in the Windows File Explorer. Edge Dev is set as the default application for PDF files. Dragging and dropping a PDF file onto Edge Dev seems to work more reliably. This was all working perfectly fine two or three weeks ago. Thanks. Jeff.
@Balaje_Krishnan Yes, thanks, I confirmed that this is fixed in 184.108.40.206. I've been using Edge Dev as my default browser for a couple of months now. It's working really well overall.
I'll add one more comment. When Edge Dev is launched from a built-in administrator account, it displays the message "Administrator Mode Detected: Close Microsoft Edge and relaunch in non-administrator mode for best performance." I'd like to be able to turn this warning off in the Edge Dev settings. It's my usual practice (and I imagine that of a lot of other system administrators) to sign into Windows servers as a built-in administrator. I'd rather use Edge Dev than the ancient Internet Explorer, and I'd rather not use a third-party browser. I'll stipulate to the pros and cons in terms of security vs. ease of use of logging onto a server as a built-in administrator.