I cannot maximize emacs. When I press the maximize button emcas cover all of the screen except the right and bottom borders.

Please tell a solution to this.

Do you have panels on the bottom and right of the screen? Areas covered by panels cannot have applications maximised over them. Please provide a screenshot to explain further.

My guess is that Emacs only allows sizes with an integer value of number of rows/columns (GVim behaves this way). I assume that you use the graphical version of Emacs, is that correct? Unfortunately I don't know a workaround if that's the case.

Quite late reply but since this was bugging me since the days I used emacs(KDE 4.3) now bugging me with gvim...finaly I dig in the window menu...as workaround go to window menu->advanced->special application settings->workarounds and set strictly obey geometry to force, this will add padding to your editor window so it will be in maximize state(don't know from how long this option is present, or I didn't know for what it is if I look it before). There's no way except one to love all this KWin options

Thank you so much for this trick, it works great to demaximize emacs (alt-F10 / alt-F10).