new dialog windows appear off screen

Hello, I am a graphic designer who uses 2 monitors at work. Almost always, if an application opens a dialog window, it appears on another monitor than the one the app is on, and often on another desktop “space.” For example, clicking on the color chit in an Adobe program opens the color palette somewhere I can’t see.

I often use an app in one monitor and have a fullscreen Youtube video on the other, so I have to pause the video, exit full screen, and try to find the space to drag it back to its native space. The problem is further compounded when I use Photoshop, because my Wacom tablet is mapped to the one monitor in that application, so if I were using Photoshop I would have to switch to my mouse and then pause the video, etc.

Hopefully you can understand how inconvenient this is. I have tried assigning apps to Desktop 1 or 2. I have tried Sys Prefs > Mission Control > Group windows by application, to no effect. I have also tried Display > Gather Windows. I would really appreciate a solution to this. Thanks in advance.

MacBook Pro 15-inch 2016

OS Sierra 10.12.6 (I cannot upgrade to High Sierra as I have an Intuos3 that will not be supported)