Over the years it occasionally happened that the 'keep on top' setting would not work, despite being set on 'top-level'. This mostly happened after a Windows crash and could easily be fixed with the good old turn-it-off-and-on-again method.
Now in the past few weeks this happened rather often, without a crash, and with the added feature of an element missing ('MyFiles' on the right). Like this:
Yes, that's what I usually do. It will work eventually.
Interesting observation: Docking the toolbar to the lower edge on the monitor in landscape always works at first try, docking it to the monitor in portrait with the vertical Windows taskbar needs several attempts. Maybe a Win7 problem?
This happened again a few times. Hoping to be gain a better understanding I created backups right before and after repairing the toolbar. Comparing the two .ocb I found only one file to be different: ConfigFiles\docks.oxc.
The problem seemed quite obvious so I created a backup of docks.oxc for the next time the toolbar would break. It sooner or later did and I restored the good version by exiting Opus and using File Explorer. Unfortunately with no success. Something would immediately after Opus started remove the <appbar edge... line and things remained unchanged. I am not sure if Opus is to blame for this, could as well be a Windows problem. Repairing always takes a few minutes of fiddling around with toolbar until it finally finds its place and stays there.
Maybe worth noting: the Opus toolbar is on the bottom of my main screen which has the Windows toolbar on the left. In most cases the toolbar broke after an Opus (soft?) crash ("Opus has encountered...").
My experience is that it's Windows (or the Windows shell, at least) that has the problem, rather than Opus itself.
Windows sometimes gets confused about which toolbars are docked where, and you sometimes see it doing things like placing a gap between the toolbar and the edge of the screen, the same size as the toolbar (or something else which was docked there), because it thinks something else is still docked there when it isn't.
If you use multiple monitors with different DPIs then it gets even worse, and docking a toolbar to the side of one monitor can move things (e.g. the taskbar) around on the sides of others. Mixed DPI in windows is a mess. (To be fair, so few things support docked toolbars these days. Opus is the only thing I'm even aware of which still does. But there are other mixed-DPI bugs in Windows that are less forgivable.)
I have a system-wide hotkey (Alt + `) configured in Opus which toggles my docked toolbar on/off:
I use Windows 10 Pro 64 bit & Opus 12.1.
After I activate my floating toolbar to my desktop do the following:
Hold the shift key and move the floater 2 very close to the top center of my monitor release shift and I have never had the sort of problem.
If I do not hold the shift key and move the floating toolbar close to the edge of my display it will dock itself to that side. And again I never have any problems with my toolbar. But I'm sorry if I've got this all wrong just trying to help.