Prior to KDE 4.8 (in other words 4.7.4) the system ran fine. No real issues. Kwin ran good, KDE desktop ran good. All apps ran good.

Upgraded to KDE 4.8.x (4.8.1 tried as well) and once that happened the whole desktop becomes unresponsive. I don't mean unresponsive like Windows XP or 7. I mean, I can't right click on the desktop (nor anything else)--as the system appears to have frozen (only it isn't frozen), except I can click on the K menu and it will pop up.

If I exit from kwin (with the hotkey) the desktop is responsive again, and I can do whatever I want. Only I don't want to use the 2d desktop.

I erased the whole drive. I then installed Ubuntu 11.10 (64bit) CLEAN. No user data, no config files, nothing. Everything is new. Install it, do updates, install Kubuntu-desktop. That installs KDE 4.7.4. That works fine. Go right from that to add the kubuntu backports ppa. Perform the upgrade to 4.8.2. Reboot (power down, then restart), and the desktop functions as described above.

Please, no one tell me to get log files.

So, any ideas? I appreciate the mind time and any help.

What graphics card does your system have? Does trying XRender over OpenGL have any impact upon this?

This is a laptop with an nVidia chipset. I've installed the stock, default, Ubuntu nVidia drivers for the 11.10 release. That installs perfectly. No errors. Again, this is a clean install as per my post above.

In Unity the effects (transparent windows, etc) work stock, no changes were made nor were required to be made. In gnome 3 (as I have tested more after the fact) everything I tried (all desktop effects) work flawlessly. In KDE 4.7.4 with OpenGL (which is the default) it works perfectly. No flaws, no delays, no freezing of any kind any where in KDE or otherwise, any desktop manager.

This started with KDE 4.8.x.

The default setting that works under 4.7.4 no longer works under 4.8.x. That default is OpenGL. The other choice (xRender) appears to work in a limited fashion. Though it appears to work the functionality is limited as it instructs me that certain plugins fail to work.

Here's a better example of what the symptoms are. I start the computer from power down. Upon reaching the KDE desktop everything seems fine. I right click on the desktop. Nothing happens. Try it again repeatedly. Nothing happens. I click on the KDE menu (lower left of the screen) and the KDE menu pops up (with some delay) and so does the left click menu I tried to bring up earlier. Same with alt+f2. I can alt+f2 and try to type but nothing happens. No typing occurs even though I have typed something. If I click on the KDE menu it goes away. I can't open any icons, can't click on anything in the system tray.

Have you tried disabling all of the effects KWin tries to use? It sounds like one of them is reacting badly with your system.

I'll try playing with them. I'll let you know which one(s), if any.

My results are as follows:

I disabled all plugins individually so that no plugins were selected; I didn't just disable effects.

Starting with "blur" I began to reenable them (and then apply). This immediately cause the same freeze like results. This forced me to turn off effects. I disabled blur again and then turned effects back on.

I chose at this time to reenable them all, except blur. Everything seemed fine.

When everything looked good I reenabled blur.

But before clicking apply I went into configuration for blur and turned off the "safe...." option. After that I hit apply. I doubt this will be a factor.

Everything seems to be working. I logged out and back in and it continued to work. I haven't rebooted the whole machine though. I'll try that next.

Ok, if turning off this Blur option turns out to be the fix to the issue, a developer will need to investigate why this happens.

Try disabling OpenGL 2 Shaders - we've another nvidia 64 bit report regarding this, but it leads to a crash (so it's just a wild shot)