Sometimes I noticed that the File Display toolbar turns all Red and I am wondering why that is or what it means? It changes back to normal after I click on it and click away sometimes. (maybe always, IDR)
And the Image TB stopped being hidden automatically when there are no image files in the display. The Thumbnail Size & Size Button controls do hide, but not the toolbar. I tried creating my own toolbar, but after reading about the Image Toolbar, it seemed it was special and I should not replace it with another. I tried that but it didn't work either... I'm a bit confused as how to make the entire toolbar hide when not needed?
See Basic Concepts: Source and Destination. (You're using custom colors so they won't match the ones in the manual, but the concepts are still the same.)
By default, it turns on when in Thumbnails mode, which is controlled via Preferences / File Display Modes / Toolbars.
If it's on all the time then you might have saved your default toolbars with it on. Close it (which you can do by right-clicking the empty space on the right of it, then choosing Close) and then use Settings > Toolbars > Set as Default Toolbar Set to save the toolbars you currently have open as the default.