Copy-and-paste, one of the fundamental operations of modern user interfaces, can be performed through various means (e.g. using the keyboard, mouse-based direct manipulation or menus). When users copy and paste between two different windows, the process is complicated by window management tasks. In this paper, we propose two new window management techniques to facilitate these tasks in the particular case of partially overlapping windows. We describe an experiment comparing four commonly used copy-andpaste techniques under four window management conditions -non-overlapping windows, partially overlapping windows, and partially overlapping ones with one of our two window management techniques. Results show that our new window management techniques significantly reduce task completion time for all copy-and-paste techniques. They also show that X Window copy-and-paste is faster than the other three techniques under all four window management conditions.