I acknowledge that this is a Steam issue, but I see it as also directly related to TSW. As my subject line indicates, I'm one of the fools who fell for checking the "Big Picture Mode" box in Steam. I have 2 monitors, the primary one being a 4K set at 3840 x 2160, the secondary being more ordinary set at 1920 x 1080. In Display Settings they are aligned with the 4K to the left, just as they are physically on my desk. Once I fell into the Big Picture Mode trap, both monitors began to come on line at a very low resolution and in very strange physical relationships. I've more or less learned how to set these errors to rights, but I'd certainly prefer to go back to their original setups. Another issue occurs when I start TSW3 (after the monitors are in correct format), which should come up on the 4K monitor, of course. Instead, the 4K monitor is switched to a low resolution, the initial first icon pops up on the 2nd monitor, followed there by the full-monitor screen shot of Cajon Pass, etc. Clicking anywhere on the 4K monitor usually moves TSW3 there. I've tried following several of the suggestions for canceling Big Picture Mode available on the web, but BPM refuses to go away. I've also thought of uninstalling and reinstalling Steam, but have yet to attempt that drastic step. Surely I'm not the only fool who opted for BPM? Please help me get rid of it once and for all?
Odd, I have never encountered an issue with being able to disable it, just unticking the box makes it stay far, far away. Make sure you also have the box that auto enables big picture if a controller is plugged in unticked.
Thanks for these tips, but I am already using those settings in Steam. Somehow, though, my system is still suffering from the after-effects of my stupidly turning on BPM earlier -- BPM itself no longer appears, but, as described in my OP, some sort of residue still affects my monitor settings.