Yep. I can now reproduce it and correct it at will.
And, I don't think this is Microsoft's fault, or some other piece of software either... This time it is squarely on JRiver (or at least, it really seems to be). I only wish I had figured it out before I got the system almost completely re-installed (for the third time). I was going through and installing everything I use, one piece of software at a time, checking it after every install. And it was consistently working fine on the new install.
I was through reinstalling all of my drivers and all of my "little utilities", and I was about to go through an install the "big" applications (Acronis 10, Office 2007, and all of those types of apps). I was skeptical that any of the "major" pieces of software were causing it, so I was beginning to feel completely stumped. Basically, I had decided to give up and just be happy that the "new install" didn't exhibit the same problem, get everything back to how it was, and then live with it.
Now, to explain something briefly... This system is normally hooked up to my HDTV in my living room via a DVI-HDMI cable. Today, I'm working on it using a different monitor, but it is still a 1080p HDMI monitor (I wanted to keep as much the same as possible). The one difference, of course, is that the monitor I'm using in my testing today is much smaller (24" instead of 50") and it sits on a desktop instead of in my living room. This turned out to be important...
So, just 20 minutes or so ago, I was sitting there waiting for something small to download (a new version of SyncBack), and trying to think of what to do next. Since I had now pretty much given up on the Windows install I did over the weekend and settled on going forward with my new, fresh install, I decided to actually go in and do my Display Customization tweaks in Windows. You know, the silly stuff like setting the desktop Wallpaper, turning on the "My Computer" and "Users" folder icons for my desktop, and stuff like that... And while I was in there, even though I didn't need it today while sitting two feet from my monitor, I decided to set my normal Display DPI size settings so that it'd be all ready to go when I hooked it up to the HDTV tonight.
So, I opened up the Displays Control Panel in Windows 7, set it to Medium size (125%) and hit OK. The system made me log off and back on again as normal. And then, after looking at it, I remembered that I had tried that setting and it still wasn't quite big enough, so I went back into the Displays Control Panel and went to Set Custom DPI Text Size. Typed in 135% and hit Apply. Again it had me log off and back on again, and then it looked how I wanted it on my HDTV.
I was about to continue installing stuff, including Office and whatnot, but I decided that it'd be a good idea to check MC before I started. I knew I hadn't really done any installs in the interim, but since I'd logged off and on a few times, I figured it'd be a good plan to double-check it.
So I opened MC up...
I immediately noticed that MC was acting completely funky about "snapping" to different sizes, and remembered this from the weekend. After I set the custom DPI size, MC refuses to resize properly (it snaps all weirdly to sides of the display that aren't there and just generally acts like a pain). Previously I had decided that this didn't matter much, since I always use MC Maximized on my HTPC, so who cares... But then I started to get excited. It was actinv weird. Perhaps this was a sign... So I maximized MC, and hit F11 to open Theater View, and...
Whammo!
The Taskbar stayed on top.I tested it a few more times, played some video, and it continued to "misbehave". So I exited MC. Went back into the Displays Control Panel and set the Text Size back to Medium (non-custom). Logged off/on, opened MC, and presto-chango... The Taskbar hides properly!
This totally makes sense. One of the things that was confusing me is that I really installed MC early in the process over the weekend. It is nice to listen to music while I'm working, so I threw MC on there (like I said) as the third application I installed in the process. However, one of the very FIRST things I did was customize the DPI size, to make working from the couch easier to deal with.
So, of course, I saw the issue the whole time. Since I was working at a desk with a smaller monitor this time, I never bothered to do this, and so never reproduced the problem!
So, I've subsequently rebooted back to my old-new hard drive (the one from the weekend that has everything ready to go on it), changed the DPI size back from Custom 135% to Medium 125% and again, presto-chango, the problem is GONE.