Safari will not open finder to upload files. Flash, Java, and Silverlight based sites.

There are a handful of sites I use that use Silverlight, Flash, and Java to open files. The sites work fine but when I try to upload images to the sites servers finder does not open. This started to happen after the High Sierra and Safari Version 11.0.1 (13604.3.5) update. The Flash/Java sites work fine in Chrome and Firefox but I have to use Parallels and IE to upload files in the silverlight based site. Any ideas? Here is an example of the silverlight site I use for digital signage. When I hit add new images it used to open finder and let me upload images.