When you double-click a file Explorer simply executes the file open command
for that file type. The exact behaviour depends on the command line and the
application, not the OS. Some applications check if there is already an
open instance and then open the file within that instance, others look for a
switch in the command line to determine how to open that file, while others
open a new instance regardless.
If you indicate what program is opening when you select those files, someone
might know how to configure the file type to force it to open with a current
instance, if the application supports that option.
--
Jeff Richards
MS MVP (Windows - Shell/User)
"potternharry" <potternharry@xxxxxx> wrote in message
news:97801249-47AD-4543-82F4-C89DBFECB926@xxxxxx
Quote:
> How can I open a file in an already running program by double click in the
> explorer?