The K Desktop Environment

13.2. Move or resize windows quickly

To move a window, press the Alt key and click the left mouse button together on the window. Alt-right mouse button will resize it. Last but not least, Alt-middle mouse button raises/lowers the window.

For more information about mouse control, please refer to "The K Window Manager Handbook".

By the way, KDE 1.1 allows you to change these mouse bindings.