Hi, I finally found the time to take a second look back at the nscleanup branch. I found that the reason for one of the test failing was not even related to the changes on the branch, so I just merged it into the trunk. So, now lxml has its own implementation for namespace cleanup when moving elements between trees. The main problem that this is meant to solve is the redundant redeclaration of namespaces that already exist in the target tree. This should now be avoided. I also expect it to be faster than the previous version - although I haven't done the benchmarks yet to prove it. So, please, everyone who had problems with this kind of bug in the past: please check if this problem is gone for your application. And everyone else who wants to help out: please check out the current trunk, build it and test it with your application to see if it still works as expected. This is a change in a rather critical place, so I'd like to have it tested before releasing it to the masses. I'm planning to release a beta version of 1.3 soon, so that it becomes easier to test. But I'd be happy to have some feedback on this before hand. Have fun, Stefan