Who else likes it when this happens on Windows XP?

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I always found it amusing when a background window stopped repainting itself, and you could drag a window all over the screen and leave trails behind.


If you want to experience this, go here: http://mrdoob.com/lab/javascript/effects/ie6/

I like that, too. ^.^

I don't remember that, but clicking on that link and playing with it was fun!

Usually that happens when the system freezes up. It really didn't happen that much when I was using Xp, but It happened all too often when I was using Win98. At the same time, when I first started using Linux, we were still stuck with the 4 series of Netscape that was statically linked to libmotif. I don't think libmotif was the cause, but a asynchronous data transfer error with Netscape would lock a Linux system up just as bad as a Windows system, if not worse. --The ony way I could get out of it was by doing a hard reboot.

Aw, love the link!! ! I seriously just played with it for 15 minutes. XD

It happens when an application doesn't process the WM_PAINT message. All they do now is automatically paint the window so that effect doesn't appear when the thread processing the window messages is busy.

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Wow you designed architecture with it!

Aw, love the link!! ! I seriously just played with it for 15 minutes. XD

Honestly, it annoys the living crap out of me, partly because I know something is glitching up really badly when it happens, and partly because it obscures parts of the screen that I want to see.

Yes, it can happen on Windows 7 if you aren't using the Aero theme.

If any of you are curious as to why this happens, then this is why. GUI (Graphical User Interface) programs are event driven, which means that there's a routine in the program that's constantly waiting for something to happen (like the user mousing over something, dragging the window, resizing, etc.). When an event happens, the program calls a function to deal with that event. There's an event in particular called WM_PAINT which a program receives when a part of its window has been uncovered or exposed. When this happens, the program is supposed to redraw the part of its window that was uncovered. However, if the program is really slow or frozen, it can't redraw its window in time, so what was drawn to the screen there is simply left there. In this case, my Firefox window, which was maximized and frozen, didn't redraw itself, whatever Task Manager had drawn to the screen was just left there when I moved the window around, leaving these trails.

Windows Vista and higher include a compositor called DWM (Desktop Window Manager), which is a program that handles all of the fancy Aero effects and transparency. When DWM is enabled, the windows no longer draw directly to the screen, but instead draw to some area of memory. The DWM then takes all of these offscreen buffers, and then puts them together (composites them) into the image you see on screen. If you're using the Basic or Classic theme on Windows Vista or 7, then the window drawing works just like XP and earlier, and this effect can happen. On Windows 8 and higher, there's no way to disable DWM, so this would never happen on those operating systems.

Everything is a window, your desktop\task bar etc is just a program called explorer.exe. If you end it your desktop will go, and windows will restart it for you (nice OS that it is).

There is a KDE on Windows initiative, if you want to check that out. https://community.kde.org/Windows
However, it's much more supported on Linux, and I find that it's a resource hog compared to other desktop environments like Xfce.