I will preface this with saying that I am using M7 but I think M6 will behave the same way.
I am able to open up build.xml files without any problem. However, if I try and open up one of my XDoclet generated Hibernate XML files, ME hangs for a good 10 seconds. It then displays the following error: “Problems Opening Editor”, “Cannot open default editor on Document.hbm.xml. Editor could not be initialized.”
If I try and right click one of my generated files, ME hangs for about 40 seconds. After the timeout, ME never displays the context menu.
If I have ME create a new XML file, paste the content of one of my generated XML files, it hangs for a while but it does allow me to paste the content. If I select all of the text and paste the content of the XML prior to making any manual changes, the XML editor does not know it needs to be saved.
All of these problems are fixed by setting the proxy server up: Preferences -> Install/Update -> Proxy Settings fields. However, I think that it would be better to smarten up the editors by having them alert the user that the external DTD references could not be accessed versus not being able to open the files at all. Just my two cents.