problem closing maximized windows

Have you installed any theme (even if you uninstalled it later)?
Are you or were you using another windows manager?
Are you or were you using Compiz or Beryl?

no, i haven´t done anything, i just intalled this ubuntu fopr the second time for this very reason. i had this exact problem before, though it only happened with the gaim window. now its hjappeninig iwth every maximized window.

Well, something must have been done, things do not change like that on their own.
Do you remember when that happened, what did you do just before?
Even something apparently very innocuos or totally irrelevant?
Anything you can remember might be a good step forward a resolution of your problem.

since the moment i installed ubuntu, the only actions i have taken have been updating, intalling codecs, and i also had problams iwth the cube graphic, it worked inthe begining, but then the rectangualr thing on the bottom right shrunk to only one cube so it did'nt work anymore. i went on this site and foudn out how to correct that. i wrote in sum code in the terminal that opened up a window where i had to find umthing and chage it from 1 to however many desktops i wanted. other than that i have'nt done anything out of the ordinary.

You see, you have at least used Compiz (which I asked you and you answered no).
And then you had a problem with Compiz, "wrote some code" which I have no idea what it did (just one command is enough to wipe your whole hard disk by the way).
Now, lets try to disable Compiz and see if you have the same problem with Metacity.
To do that, disable desktop effects and try to maximise and then close the windows.

ok so i disabled dektop effects, and now everythings is working normally. but i wujld like everything to work normally with desktop effects.

Thanks Cesare Tirabassi, that solved my question.

I'd just like to mention that I've got the exact same problem (I also had trouble with the desk icons disappearing/not working correctly and used the described hsize-setting-solution to fix that). However, reinstalling compiz did not fix that sometimes maximized windows can't be closed or minimized again by the buttons in the top-right corner. I do have a custom theme installed, but this does not seem to matter, judging from the op's experiences.

After diddling around with that Desktop Effects dialog box so that the two boxes are unchecked _and greyed out_, the maximize/unmaximize problem was resolved on my Ubuntu 7,04 system (running with Compiz). The same bug also affects the LimeWire P2P program - all you get is a blank window - and the above fixed that problem also.