I am a new Painter 2019 user and need to set up Painter on my Tablet (Art-Pen) while following video tutorials on the main monitor (iMac Mojave). Since Painter UI floats above the desk top or document, It can't be easily moved to another display. However, the document containing the artwork can be moved to the tablet display. Can the UI be pinned to the document or can the entire UI be grouped so it can be dragged to the tablet monitor?
To my knowledge, this isn't possible...however, when I run a two-monitor on my Mac setup I do the following:
1. Go the Apple System Preferences
2. Go to Displays and select the "Arrangement" tab
3. There is a little white menu bar...drag it to your secondary display
4. It should be easier to setup Painter on that display now...for example if you have not customized the layout, simply 're-toggle' the layout by going Window > Layout > Default and it should tidy up nicely on that display.
NOTE: if you do make customizations, consider saving that as a new layout. If you are frequently changing between the two monitors (and they have different resolution) consider making a layout for each monitor.
Hope this helps a bit...