Window positions on Mac triple screen don't hold
On V. 15.0 I use a 27" 4K monitor arranged above two smaller HD monitors when using InDesign and Premiere Pro, for generous screen real estate. PrePro remembers to place the Program monitor on the big screen when a project is loaded. InDesign, even when the workspace is saved explicitly as "Triple," with Panel Locations and menu Customizations options checked, does not respond and loads only into the two lower HD monitors.
Based on user comments, closing this.
Adobe InDesign team
Loren S. Miller commented
I'm retracting this report-- it now seems to be functioning as expected, honoring the selected workspace.